To be able to get the dynamically generated CSS we would need to be able to call Pega's packaging code with enough information that it thinks it is the same device and portal. The first part should be fairly easy. We would need to be able to pass the same UserAgent string and other associated headers from the original request. So the first pass of the requirement should be that we are able to rewrite a URL capture in TeaLeaf to a different URL and be able to selectively include headers from the original request (by virtue we might also want to exclude others like session IDs). The second part is potentially a little more hacky. We need some way to inject the name of the portal into the URL, so possibly the easiest generic way for them to achieve this would be a way to record arbitrary session variable that we could name and set values of which apply to the whole session. So for arguments sake the provide TeaLeaf.setSessionVariable('portalName', 'myPortal'). This way we could capture the portal name or anything else useful for replaying the session or anything that came to mind (It is a bit of a get out of jail free card). Then in their URL rewriting rules they let you say user a regexp to extract data from the existing URL but also let you include symbolics like say match /(w+)\.css.*/ then when we write our uURLwe could say https://mywebservice.com/\1.css?portal={session.portalName} (https://mywebservice.com/1.css?portal=%7bsession.portalName%7d) this would be rewritten as https://mywebservice.com/cssfilename.css?portal=valueOfPortalName.

I think with both of those in place it would be easy for us to create a web service that could generate the same CSS (not to trivialize it as we still have a little work in writing the web service).