The STLport bundled with the SunStudio11 generates alot of warnings. I beleive most compilers have a way to disable warnings from certain source files, like this:
Can't help with turning the warnings off, but when I last looked at SunStudio, it shipped with two STLs - an older one for backward compatibility with earlier compiler versions and STLport. Might be worth checking if you're using STLport before trying to trying to turn off the warnings.