Hello,
We never tested SSMA with DB2 running on Bluemix, but from what I understand, Bluemix is IBM's Cloud offering, where they appear to be running LUW version, which is supported by SSMA. Unless there are changes they've made to catalog views or access model - it should work.
As to SSL - this is not really an SSMA problem, but rather a configuration for the OLE DB provider you are using to connect. It appears that you are using "Microsoft DB2 OLE DB Provider". The easiest way to craft correct connection string and test the connection would be to use the Data Access Tool. You may want to provide "Certificate Common Name" to enable SSL/TLS in the provider.
Regards,
Alex.