How to force SQL developer to use imp/exp command while import/export
Not going to happen

The Original exp utilitie became DESUPPORTED as of 11.1.  Additionally, the 11.1 version of the database is no longer supported either.  SQL Developer isn't going to be "patched" to support unsupported Database version or unsupported database features.

For more information you can read the Compatibility Matrix for exp/imp which has Oracle Doc ID 132904.1 NOTE : You must have a valid support contract (and account) to access the Document. (copy+pasting information is against Oracle's term of use)

The imp utility seems to still be around for importing old exports.

Workaround

Learn to use the command line.