Cannot handle namespace aliases

[zappy-shu]

When attempting to transform elements with namespace prefixes, the transformer locators throw an error:
Failure/Error: return parent_source_node.xpath(xpath) Nokogiri::XML::XPath::SyntaxError: ERROR: Undefined namespace prefix: a:basictransforms_namespace_replace

Example source:
<basictransforms_namespace xmlns:a="http://a/"> <a:basictransforms_namespace_replace a="aaa" /> </basictransforms_namespace>

Example transform
<basictransforms_namespace xmlns:a="http://a/"> <a:basictransforms_namespace_replace b="bbb" xdt:Transform="Replace" /> </basictransforms_namespace>