I suggest:
First, a redirect service with a redirect-url of "http://192.168.1.55:7178/forms/frmservelet?config=test123"
Then, a content rule listening on port 80, /*, forwarding to the redirect service.
Then, a content rule listening on port 7178, /*, forwarding to the redirect service.
Finally, a content role listening on port 7178, /forms/*, forwarding to the appropriate services.
This will ONLY work if there's no other content except forms/* to be served on port 7178, and no other content to be served on port 80.