Dropdown Certificates in Adapter SSL Error

We have changed in Exchange Profile (Property: com.sap.aii.connect.secure_connections = all) to use the secure connections between the SAP PI components. This is working fine so far - but when we are trying to chose a certificate

This happens for all kind of channels where we want to chose a certificate from Keystore

Looking into the Log Viewer i see:

I have imported the SSL Certificate (including the CA Certificates) of the Java Server into the TrustedCA.

Has someone an idea?

BR Helmut