Changed the base type for the restriction from xsd:duration to xs:string to allow the empty value.
The current approach wasn't correct and we can't depend on the XSD 1.1 types because our schema is 1.0.
--- a/2.0/core/schema/xsd/XForms-20-Schema.xsd Wed Apr 10 17:50:40 2013 +0200
+++ b/2.0/core/schema/xsd/XForms-20-Schema.xsd Fri Oct 31 10:45:56 2014 -0700
@@ -1582,7 +1582,7 @@
</xsd:simpleType>
<xsd:simpleType name="dayTimeDuration">
- <xsd:restriction base="xsd:duration">
+ <xsd:restriction base="xsd:string">
<xsd:pattern value="([\-]?P([0-9]+D(T([0-9]+(H([0-9]+(M([0-9]+(\.[0-9]*)?S
|\.[0-9]+S)?|(\.[0-9]*)?S)|(\.[0-9]*)?S)?|M([0-9]+
(\.[0-9]*)?S|\.[0-9]+S)?|(\.[0-9]*)?S)|\.[0-9]+S))?
@@ -1593,7 +1593,7 @@
</xsd:simpleType>
<xsd:simpleType name="yearMonthDuration">
- <xsd:restriction base="xsd:duration">
+ <xsd:restriction base="xsd:string">
<xsd:pattern value="([\-]?P[0-9]+(Y([0-9]+M)?|M))?"/>
</xsd:restriction>
</xsd:simpleType>