How to get attributes from other categories

1090 [f60] <AttributeDesignator
1091 [f61]     MustBePresent="false"
1092 [f62]     Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource"
1093 [f63]     AttributeId="urn:oasis:names:tc:xacml:3.0:content-selector"
1094 [f64]     DataType="urn:oasis:names:tc:xacml:3.0:data-type:xpathExpression"/>
1095 [f65]