As far as I know there is no out of the box feature for this. I could envision you writing a java application that does the following:
Use LC User Management APIs to query LDAP for information like: name, organization, department, password (? - not sure you can do this with our LDAP APIs)
Call the Java utility mentioned in the JBoss installation docs (not sure it's part of the installers for other app servers) for creating self-signed certificates, using the information queried in step 1
If you wanted to use these certificates for server-side signing then you would need to import them into LC using the LC java APIs. I've never tried it but I think that should work.