the method accesses the GML schema of the feature types being part of the passed
FeatureTypeConstraints and extracts the geometry property definition. The names of the
geometry properties will be added as PropertyPath's to passed list
Parameters: layer - Parameters: ftc - Parameters: pp - the list of property paths throws: OGCWebServiceException - throws: SAXException - throws: IOException - throws: XMLParsingException - throws: XMLSchemaException - throws: UnknownCRSException -