combining pattern values?

Hi,

Is there some way to combine pattern values when defining a new simpleType?  For example, suppose I have a simpleType called IntegerString:

	<simpleType name="IntegerString" base="xsd:string">
		<pattern value="\d+">
	</simpleType>

and a simpleType called UnitsString that can be expressed either as:

	<simpleType name="UnitsString" base="xsd:string">
		<enumeration value="cm"/>
		<enumeration value="in"/>
	</simpleType>

or:

	<simpleType name="UnitsString" base="xsd:string">
		<patter value="cm|in"/>
	</simpleType>

Is there a way to create a simpleType based on these two simpeTypes that would allow the value, say "23cm".  Clearly it would be simple enough to create a simpleType on its own to support such an expression, but there are cases that the combination of simpleTypes would be desirable.

thanks in advance, Chuck

Chuck Han, Data Architect
Autodesk, Inc.
+1.415.507.8742