Multi-valued SAML attributes not supported - any ideas/workarounds?

I wrote an iRule to parse multi valued attributes from a federated SAML token and put them into one string with each element separated by a pipe:

when ACCESS_POLICY_AGENT_EVENT {
if {[ACCESS::policy agent_id] eq "di_roleParse" } { 
     Get the raw SAML Assertion
    set samlAssertion [ACCESS::session data get "session.saml.last.assertion"]
    Parse the XML and only extract the Role claim, also trim the first 76 characters so we dont keep all the attribute junk
    set roleValues [findstr $samlAssertion "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/role" 76 ""]
    delete all the XML attribute value openers
    regsub -all "" $roleValues "" roleValues
     replcae all the XML attribute value closers with space pipe space
    regsub -all "" $roleValues " | " roleValues
     assign to a custom variable
    ACCESS::session data set session.custom.attr.role $shortRoles
    }
}