In order to pass basic authentication information in the header to an application that you have set up as a webProxy in uPortal. You will need to use the BasicLocalConnectionContext:
1) Add the attached org.jasig.portal.security.BasicLocalConnectionContext to the source area and redeploy. Note: this code will be included with uPortal 2.5 and you won't need to download it here.
2) Restart tomcat
3) Define a web proxy channel
4) Define org.jasig.portal.security.BasicLocalConnectionContext as the LocalConnectionContext implementation for that channel
You should now have a WebProxy channel using the LCC to send authentication credentials to a remote server.