Hi there Lanier
You have almost the same set-up as me - I use a Line 6 TonePort UX2 for my soundcard, my VS-20 as a DAW control (and occasionally to record using the COSM Effects) and an Edirol (now Cakewalk) PCR-800 MIDI controller.
There is no reason why you can't record a completely dry guitar signal using your TonePort. Just open up GearBox or POD Farm (whichever you use) and create an empty' preset. If you're using GearBox, turn off all the effects in the chain and select 'No Amp' and 'No Cabinet'. If you're using POD Farm, simply open any preset and then right click in turn on all the amps/effects and select
Delete to remove them from the effects chain.
If you're likely to use this a lot to record dry, I'd suggest saving it as a preset. Just make sure you use
Save As and rename the preset - if you just use
Save you'll overwrite the preset you opened in the first place.
Here's how a completely 'empty' preset looks in GearBox:
And here's my 'Empty' preset in POD Farm 2:
If I am recording dry direct into my TonePort, I often send the signal through the POD Farm Compressor - this helps to get a nice strong, even signal to record with:
As far as hearing any of the softsynths in SONAR, your TonePort will work fine.
You certainly don't need to spend any more money - you have everything you need to do exactly what you want.
Hope that helps, but if there's anything else you need explaining, just ask away!
Steve