OK. Lets try this. For maps, Google for SOF2 maps. You can check this site too:
Clicky thingy
Second...your .cfg's. Should be two places for your sof2mp.cfg and associated autoexec.cfg, the ...base/mp dir and ...osp dir. You're probably hitting a server with OSP running when your .cfg seems to disappear. Make a copy of the .cfg's in the first and copy/paste to the second. If you change one, you'll have to change the other. Lemme know if that's not the problem.
Third, the weapon script you want may look like this:
bind MWHEELDOWN "weaptoggle primary secondary pistol"
bind MWHEELUP "weaptoggle primary secondary pistol"
Again, let me know if this doesn't werk.