Custom claims with Sitefinity 10 and external STS

Hi all

We have successfully implemented a custom external authentication provider with Sitefinity using this sample. gist.github.com/.../bb36a069e8cd210c2f68d04b3368fd57

We are trying to enhance the Sitefinity identity with additional claims from the STS like address or phone number information, with the intention of accessing them from the  ClaimsManager.GetCurrentIdentity().Claims collection in our widgets.

But no matter what claim we add in the SecurityTokenValidated event handler, Sitefinity does not add them to its own collection of claims - they get lost in translation.

How can we capture the inbound claims from the external STS and access them from our Sitefinity application?