SSOv2 BIG-IP as IdP SP variable needed for iRule log

Does anyone know the variable name for the SP connector found in the APM notice log example below?

 

SSOv2 BIG-IP as IdP (/Common/idp-name-1) sent SAML Response (size: 7872) to SP (/Common/app1-prod)

I am trying use an iRule to write the SP-connector name in a syslog along with other data. This is the only item I cannot dynamically reference.

 

Bonus scenario would to then have the "/Common/" removed and only write out to log "app1-prod"