Need assistance with html rewriting

Hello, I have a WebSphere application with the following path: Browser -> f5 -> Apache -> f5 vip -> WebSphere. The apache is there because I have multiple types of traffic on the main ip (static/dynamic) which needs to be routed. Once Apache determines that it needs to send the request to WebSphere it does a rewrite to the vip (10.215.196.12 on port 80). The vip is set up to go to the WebSphere server at 10.215.21.4 port 12000. The application is building html and it is putting the vip address into the html along with the port. So the html tag looks like: http://10.215.196.12:12000/mylink Is there a variable I can inspect to translate that html content back to the original url in front of the apache? Or do I need to process all of the html and do a rewrite when I find the specific ip address? I'm trying to find a way to do this without being required to hard-code ip addresses in an irule or stream profile. Thanks in advance!