It's Todd's forum, but hope he doesn't mind me bringing up what Gary Willis has to say about this sort of thing...
Basically, Gary says if the other players think it's ok for them to drop out when you the bassist are soloing, make it clear to them you will have no problem laying out while THEY solo...
See how they like THEM apples.
Just because you are soloing is no reason for everyone else to drop out.
What usually works for me at a jam session is to politely ask the guitarist or pianist up front if they would please comp behind you when you are soloing - a good, confident, generous player won't object - it's what they ought to be doing anyway... and it's good comping practice for them, so everybody wins.
It's a jam, right? So if they give you attitude or whine or they just don't do it, drop out the next time they solo.
JMHO
p.s. - my *other* suggestion: know the melody well enough to keep that going along in your head while you solo - this gives you a "reference". It's hard at first, but does get easier the more you work at it.