The actual version of SailPoint (6.3p3) contains an issue that will break SP initiated SAML authentication with ping! Federate.
When the request is created, SailPoint uses the Entity ID value also as the value for the SPNameQualifier. Federate will try to find an affiliation with this name, but cannot find it. When you try to create an affiliation in Federate, it will not work because NameQualifier and Entity ID are equal.
Unfortunately, this cannot be fixed since this is hardcoded behavior in both products. SailPoint is aware of this behavior and will release a fix with 6.3p4.