Hi, have you tried starting wvdial from the run dialog of your window manager (alt+f2 in fluxbox/gnome/kde/xfce etc,etc..) ?
You could write a kdialog/zenity driven shellscript (check the manuals on those two if you have them ofc.)
other than that you could try this:
# wvdial start/stop script
if $1='start'; then
if $1='stop'; then
killall -HUP wvdial
save it as wvdial.sh, give it executable permissions (chmod +x wvdial.sh) and then just ./wvdial start, then wvdial stop. You are not supposed to keep the terminal going if this works.
Note that I am not familiar with wvdial or backtrack, I just want to help. Dunno if I have syntax errors, I'm on a windows box right now and can't check the shellscript, but you could try it, i suppose it won't hurt
Hope this helps/gives you a hint on how to do this.