I've got it set where a supporter can have 3 blogs without ads and with premium themes.
If I log in as a supporter and create a new blog (the 2nd one) and click "supporter" - "disable ads", it says:
As a Premium Member, you can have a total of 3 websites with premium themes and without ads.
Maximum blogs: 3
Currently disabling ads on: 0
Nothing below...no button to actually activate this function?