The v1 beta of StarterSTS has an updated relying party configuration section. This allows to “plugin” the STS into ADFS2 or Sharepoint as a claims provider.

Here’s a quick walkthrough for ADFS2:

Register StarterSTS as claims provider in ADFS
This is really easy. Simply go to the ADFS2 configuration console and add a new claims provider. Then point the wizard to the StarterSTS WS-Federation metadata file (either by URL or using a file path). Afterwards you have to add some claim rules – to get started you could add a pass-through rule for the name claim.

You will also need to export the ADFS2 certificate that is used for token decryption.

Registering ADFS2 as a relying party in StarterSTS
The next step is to register ADFS2 in StarterSTS. This is done by modifying the relyingParty.config file (in the configuration sub folder). You need three things for that – the ADFS issuer URI, the physical address of the ADFS2 sign-in page and the ADFS2 token encryption certificate. The certificate could be either imported into the certificate store or you copy it to ~/App_Data/certificates.

The config entry looks similar to this:

<add realm=“http://<adfsname>/adfs/services/trust“
     replyTo=“https://<adfsname>/adfs/ls/“>
  <certificate filename=“tokendecryption.cer“ />
</add>

HTH