<enumeration> of duration types

Hi,

should a value of "P12M" be considered a valid value for a "duration"
based simple type with an <enumeration> value of "P1Y"?

While XSV 2.8 rejects the value, Xerces-J 2.6.2 and MSXML 4 both eat it.

If the value is allowed: Should the comparison behave like in
"3.2.6.2 Order relation on duration" of XML Schema part 2?

Regards,

Kasimier