RSA and WebServices

[styko]

I'm going to use WebMethod GetRSAParameters in my c# application which
returns RSAParameters object. But when I'm trying too include
System.Secrity.Cryptography namespace and when I'm writing something like
this:

RSACryptoserviceProvider rsa = new RSACryptoServiceProvider();

RSAParameters params = webService.GetRSAParameters();

compiler complains that reference to RSAParameters is ambiguous. When I'm
trying to use fully qualified names and cast from WebService.RSAParameters
to System.Security.Cryptography.RSAParameters, casting fails.

How can I manage with this problem.

Thanks for any help!!!