the S8300B runs CM 5.2 just fine, but, only in "standard" memory model, it will not support "large" memory model, so it cannot be an LSP of an S8730 running CM 5.2, which only supports "large" memory model.
A standalone S8300B works fine for CM 5.2, I have it loaded on several of them already.
Mitch
AVAYA Certified Expert