Hi,
Are you doing integration with UPS?
The content type issue was not due to UPS side. It was due to the way the port was configured in SAP.
Check this one first:
Once you created the proxy in SE80 and you set up your logical port in SOAMANAGER. It should automatically generate your SM59 connection of type G (HTTP). The generated RFC name can be see in your port in SOAMANAGER as well.
Do a test connection of the same in SM59. It should give you text/xml in the request and response.
Check this and get back.
Regards,
Praba