Regex problems with XMLBeans

I have an Axis2 1.6.1 web service that has 1 regex in the WSDL schema.  
The WSDL/schema snippet is below.

<xsd:complexType name="hazmat">
<xsd:sequence>
<xsd:element minOccurs="0" name="hazmatCode" nillable="true" 
type="tns:hazmatCode"/>
<xsd:element minOccurs="0" name="hazmatFlag" nillable="true" 
type="tns:hazmatFlag"/>
</xsd:sequence>
</xsd:complexType>
<xsd:simpleType name="hazmatCode">
<xsd:restriction base="xsd:string">
<xsd:whiteSpace value="preserve"/>
<xsd:pattern value="^(NA|UN).*"/>
</xsd:restriction>
</xsd:simpleType>

I know the regex pattern of ^(NA|UN).* is valid as I have tested it.  
However, each time I send a request with a string that matches the 
pattern I get an error like "string value 'NA1122' does not match 
pattern" when performing validation against the schema.

I have used simple patterns before with XMLBeans and they have worked 
fine.  Have I defined the regex incorrectly or does the XMLBeans binding 
have problems with regex?

Any and all information is appreciated.

Thanks,
T