Compatible with Totemoemail?

Hello.
 

I work as a tech on CSC/Saab.

I've got a incident regarding PGP & Totemoemail.

Our users have PGP and a external customer has Totemoemail, they say that PGP & Totem is compatible and share encryption keys.

I'm not able to find any evidance that this is true, should it work?

They only get a "Invalid Key" when they try to Encrypt/Decrypt emails. How should i continue?

Best Regards

Jonathan