REGEX syntax for APM NTLM Auth

I have a very similar situation. I'm running 11.1 HF1 and doint multiple AD domain authentication. With 11.1 APM has no issue identifying the domain if the user types domain\username but if the user types domain/username it sets the username as domain/username and of course user is not going to authenticate. So I'm writing a regular expression to identify if the session.logon.last.username contains / to take the domain value up to the / and set the session.logon.last.domain to that value and set the rest of the string as the session.logon.last.username. I have the expr {[mcget {session.logon.last.username}] contains "/"} and I need to embed the action to set the domain and username values into variables by using ^|\/.+ which just takes the domain info and .+\/|^ which just takes the username. Any ideas how I can embed that info the contains /? Thanks for your help