The guid type defines a string representing a GUID (aka UUID).
Example:
<originalPaymentID>616129bf-3ee0-4e63-9998-2fed6e85b7b7</originalPaymentID>
XML Schema:
<s:simpleType name="guid">
<s:restriction base="s:string">
<s:pattern value="^[({]?(0x)?[0-9a-fA-F]{8}([-,]?(0x)?[0-9a-fA-F]{4}){2}((-?[0-9a-fA-F]{4}-?[0-9a-fA-F]{12})|(,\{0x[0-9a-fA-F]{2}(,0x[0-9a-fA-F]{2}){7}\}))[)}]?$"/>
</s:restriction>
</s:simpleType>