The authoritative documentation for WS-Trust / STS integration is at https://docs.jboss.org/author/display/JBWS/WS-Trust+and+STS . You need at least JBossWS 4.1.x series, which basically means JBoss AS 7.2 / EAP 6.1 or greater / WFLY 8, unless you can and want to upgrade the ws stack in the container.
Speaking of SOA-P platform, the STS / WS-Trust integration is likely coming in version 6, but you'd better check with your customer contact.