In some of my larger implementations we've implemented service catalogs which sit in front of the Service Manager world in order to provide a holistic picture of all of the services offered from IT to the business. In this scenario we've been able to serve specific customer needs, while still using the Service Manager service offerings and request offerings. This has also allowed us to serve some scale scenarios better than if we just used the out of box portal. That said, we ran into a problem where after submitting an incident, a user would get directed back to the basic out of box portal. This is NOT what we wanted, as we wanted the user to get directed to the non-out of box service catalog experience.
This was actually simpler than we originally thought it would be. In the "settings.xml" file on the web content server you can modify a key which allows you to insert static addresses for the Service Manager URLs.
You can find the "settings.xml" file usually in the "C:inetpubwwwrootSystem Center Service Manager PortalContentHostClientbin" directory wherever your web content role is installed.
I'd start by backing up the original copy of the file.
Then search for the following line and change the URL to the desired target URL:
Here it is in context. Note that you can also make other changes, such as colors and the quantity of items shown on a paticular page:
I'll note that initially it didn't appear to work. In fact, it didn't even work after I performed an iisreset. I finally found that I needed to refresh the cache on my client in order to get the settings.xml to take effect. There is a handy way to do this centrally here