MS Enhanced Cryptographic Provider - key wrapping using RC4   

Hi...

I'm developing own RSA provider, MS compatible... And can't understand
implementation symmetric key wrapping using RC4 in MS Enhanced
Cryptographic Provider... It not correspond with RFC 3217, describes
block ciphers... May be anybody meet description of this algorithm?
Thank you...

date: Tue, 1 Jul 2008 12:08:35 -0700 (PDT)   author:   Vladimir