Has anyone managed to get TLS working between Android Linphone and Freeswitch?

I've done the basic TLS setup as per https://wiki.freeswitch.org/wiki/Tls

I then convert the CA cert from PEM to DER format with:

openssl x509 -inform PEM -outform der -in cafile.pem -out fs.crt

I place fs.crt on a webserver and point my Android browser to it.

When I click on fs.crt, I get the default Android Certificate installer popup, but it always says:

"Package contains: one user certificate"

ie: it thinks it is a user cert rather than a CA cert.

Android appears to be a real pain to add a CA to its trusted credential store.

Really interested if anyone has managed to get Android to import the CA cert.

Thanks

Peter