I uploaded a newer version of the SM3 schema to the following location:
http://ftp.pwg.org/pub/pwg/sm3/schemas/
See the zip file: PWG_SM_3.0_v2.901.zip
The following .xsd files were updated from the earlier version (thanks to Joe Murdock).
PwgCommon.xsd - fixed namespace ab=nd annotation issues for XML Spy validation
PwgSecurityOpMsg.xsd - updated for change from SecurityAttributes to SecurityElements
PwgSecurity.wsdl - updated for change from SecurityAttributes to SecurityElements
Security.xsd - the update IDS security schema
PwgWellKnownValues.xsd - updated with new values previously maintained in security.xsd:
ClientTypeWKV - a standard list of client types
DeviceRoleWKV - a list of standard device roles
ServiceRoleWKV - a list of standard service roles
UserRoleWKV - a list of standard user roles