Well, first and foremost: you won't be forced into using the 64bit version of SONAR X2 just because you're using a 64bit OS. The 32bit version will install and function very much like X1 on XP with the plugs you mentioned.
BitBridge comes with X2. It'll allow the use of 32bit plugs in the 64bit version of SONAR. No such luck with DirectX plugs, though. 32bit DX plug-ins will only be available in 32bit SONAR. It should work with the VST plug-ins you mentioned.
JBridge is another means of achieving the same goal. SONAR has built-in support as of version 8.5. But this is third-party and costs a few bucks. A lot of users prefer it over BitBridge, depending on how much they rely on it and what plugs they're using. But, chances are good that BitBridge will work for you.