Paypal DLL Mods
It isn't that hard - I just did it. And you don't need to do a thing for Website Payments Pro, only for Payflow Pro.
Download the new SDK from Paypal.
Scroll all the way down... to .NET SDK for Payflow Pro v4.31
Install it on your server - go to the install dir...
C:\Program Files\Payflow SDK for .NET\COM\
Read the "ReadMeCom.txt" and use the files they provide to help you out. All in all, it should take you about 30 minutes to complete.
There are few minor changes to "PFPro_VB.asp" and you're good to go.