WCF Claim question : different claimset on IIS then when selfhosted

Hey,

I have a strange situation.
I have created a WCF service that takes a client certificate (coming
from a smartcard).
When I check the AuthorizationContext and look for the claimset
corresponding to that certificate I can find it.
Then I look to the issuer of that claimset, looking if it was issued
by the right authority:
When I run this service in a console (selfhosted) I get a
System.IdentityModel.Claims.X509CertificateClaimSet as the issuer of
the client certificate. when I run the same service in IIS (same code,
app.config=>web.config) I get a
System.IdentityModel.Claims.X509CertificateClaimSet.X500DistinguishedNameClaimSet
as issuer containing much less information!!

How can this be? The behavior is different but it's the same
service ...
Is it a rights issue?

Thanks in advance
Kristof