SAP url change from http://sapdev.company.com:50100/irj/portal to http://my.company.com/comcheck

Dear Experts- I am trying to change the portal URL ( we are Netweaver 7.31) from http://sapdev.company.com:50100/irj/portal to http://my.company.com/comcheck I followed the below options. 1) http://wiki.scn.sap.com/wiki/display/EP/Change+Portal+URL 2) as well as URL Alias manager ( created Desktop rule also) this feature in 7.3 http://help.sap.com/saphelp_nw73/helpdata/en/48/1d5d0171364269e10000000a421937/content.htm after I enter in browser http://my.company.com/comcheck I am getting below error 404 Not Found SAP NetWeaver Application Server Error: Requested resource does not exist. SAP Technology Troubleshooting Guide Details: Go to main page of this application. Please advise thanks kaveti