Ok. you need standard XML signature, like XAdES.
RSACryptoServiceProvider and NCryptoki are not compatible. RSACryptoServiceProvider uses CSP, NCryptoki works with PKCS#11 module.
XML Signature has a PKCS#1 value in the XML field Signature. To produce such a field you can use Session.SignInit, Session.Sign.
The rest of the XML fields are here: http://www.w3.org/TR/xmldsig-core/