I assume you've tried the latest free bass pack ?
Take any good bass profile and put the following in front of it:
- Transpose, -1 octave. You can fiddle with the various options like Pure Tuning and Formant Shift if you want, sometimes they're helpful. Sometimes it's also good to have the transpose set at, say, 90% wet instead of full, so your original signal helps fill in some of the higher harmonics for the bass signal.
- Compressor. Crank it up, just smash the shit out of your signal - with a simulated bass, that's generally the only way it'll sound good because you can't get much of a nuanced bass sound out of a guitar. You could also turn up the Attack knob a little to emphasize the pick attack.
- EQ. Since a transposed guitar usually sounds like crap, you can use this to carve away most of the signal. For starters, I'd set the high-cut down to at least 5kHz, and then experiment with boosts or cuts all over the place to get rid of the bits that sound wimpy, like a transpoed guitar, and boost the parts that sound meatier, like a bass.
For a profile, I always end up coming back to Gallien Krueger C. It's on the rig exchange.
Robman, thank you. I downnloaded both bass packs. But - as always - would not know where to start. So many profiles, so many options.
Fortunately, Lokasenna was generous enough to write this little tutorial for me. Thank you so much. I am going to record today with exactly those tricks and hints in mind and
post the recording. All that sounds understandable. I do love 
step-by-step guides in order to get started.
Thank you, again, Lokasenna 
The first profile doesn't sound bad, I think it just has too much midrange so you aren't able to turn it up enough to feel the bass - the region from around 800Hz to 2kHz can be really bad for this, because just about every instrument in the band is making noise there, but the bass can often be removed from that range without sounding bad.
Try to figure out what frequency the "click" is living at, and then add a wide, deep scoop to cut out everything in between that and the lows - I can usually get away with cutting from 400Hz to 3kHz on my bass without losing too much. If it feels like you're killing your tone by doing that, you can always duplicate the track, EQ the duplicate to ONLY have that midrange, then run it through some distortion and compression so you can blend it in behind the main bass tone without it overpowering everything.
I just remembered another awesome bass profile - search for "Avalon Bass" and you should find it.
The Squire Jaguar Bass is a good one.
This may be a strange solution to your issue, but if you have a guitar laying around that you don't use that much and don't mind doing a little work on, consider putting some thick strings on it. A lot of 8-string guitarists (I have one that I like to noodle around on) tune their guitars EBEADGBe or F#BEADGBe. Most 8-strings are 27" scale, so a 25.5" scale might be a little floppy, but you could go through Stringjoy (they're awesome, and their customer service is second to none, but they are a little pricy for a custom set of strings) and customize a nice, thick set, like you might see on a Fender Bass VI. Something along the lines of 17-90. Then you could tune it to standard, just an octave down. Or maybe F#BEAC#f#, and transpose down only a couple steps. Probably need to adjust your intonation and file down the nut a bit, but, without buying a bass, it's a decent option, and you'd basically have a cool, baritone guitar at your disposal, and a fun project to boot. I've played through some bass profiles with my 8-string, and, while they are REALLY close in tone, it's still no actual bass.
Also, I know money doesn't grow on trees, but if you're really going to get into more bass, consider actually picking one up. Transpose works... okay, but I've never found any transpose or pitch shift algorithm that I liked enough to use on a normal basis, primarily due to latency and tone, and especially when moving more than a few steps away from the origin pitch. Fender Squier basses are surprisingly good these days (my Fender Squier Strat from the 90's that I learned on, in comparison, is a piece of junk). A buddy of mine picked up one used, set it up himself, and put in new pickups. Sounds (and plays) actually really good, and, with the pickups, I don't believe he spent more than about $300 on it all. Ibanez makes some good options for inexpensive too - I have a SR506 (6-string), and, new, they're about $600, but you can find them used pretty much any day of the week, and, less strings = less $. Step down to their SR300 series and you can basically get a new one for about $350, and they're pretty solid right out of the box.
thx doug for your comments. we are d'accord. only the real thing is the real thing.
my best friend is a collector and bass player. he has more than 40 basses, some of them 5000.- Alembics, a fender from the 60ies, human base, and so on ...
guess what, when i visit him, the squire with the maple fretboard is may favourite, no kiddin' 
so, this one is on my to-do-n-to-buy list!
IMHO, Music Man Sub (I think that's what they're called) is the best value out there considering the sound.
They're cheap 'cause they're not made at the EB factory in the US, but the price is disproportionately-low when compared to the uber-expensive, US-made counterparts. Fantastic, unbeatable value IMHO.
