Welcome to the Magix Sound Forge users forum @Adam-Bialek.

I do not think Vegas 11 and Sound Forge 11 were ever bungled together. There are more versions of Vegas than SF. So you need to check exactly which version number of SF you purchased.
That said... Do you have Sound Forge Audio Studio 11 or Pro 11? Did you download the SF installer from the Magix Service Center? Either way, the application installs to your PC and is activated afterwards. If you mean, you have installed it, but cannot activate it, you must have a valid SF-11 serial code, which is unique and different than your Vegas serial.. and.. the email address you used when SF-11 was initially activated through SCS (Sony).