Toke is null in paypal express checkout

I am working with pay express checkout in asp.net(3.5 or 4.0) with website template.I have added its SOAP API reference from below mentioned URL:

https://www.sandbox.paypal.com/wsdl/PayPalSvc.wsdl. when I call setexpresscheckout method to get token value then it always return null as a token value and send token value in Any variable which is useless for me.

if anyone can help me to get a token value in token property instead of Any property.Then Plz .......... do it fast