APM BIG-IP as SP with SAML artifact response

keep working with SAML and BIG-IP as SP, trying to get it to work with another IdP then before. this one doesn't return the SAMLResponse in a POST but performs a GET with a SAML artifact (i.e. GET http://bigip-sp/saml/sp/profile/post/acs?SAMLart=.......). is that something the BIG-IP as SP supports? do I need another url to "GET" that?