WIF-Authenticate claim-based Share Point site by token passed from a winform client

I followed this link and did it

http://msdn.microsoft.com/en-us/library/gg251994.aspx

But our scenario is litter different:

We have a WinForm client, Wcf services(hosted as windows service), Sts (hosted as windows service), claim based share point site for reporting

As the link above, I have to create a a开发者_C百科sp.net web service as an identity provider security token service (IP-STS), but we don't want to use IIS at this time. we want it to be able to run as a standalone service, without any dependencies. Keeps it simple for the server setup and maintenance. So how can I keep the token when user logged in to WinForm client and then when user click a link from client to view report, we will use it to authenticate to SharePoint(use our STS-hosted as windows service) without creating a new IP-STS hosted in IIS and force user have to input their information again to authenticate to SharePoint.

Any thoughts or help would be greatly appreciated!