@Steve:
I suppose you have put <vault> on the wrong place in the XML file. It cannot be used on arbitrary place you want. If you use it in standalone.xml, the sequence of tags MUST be following:
<extensions>
<system-properties>
<paths>
<vault>
<management>
If you have only <extensions> and <management>, then <vault> must be exactly AFTER </extensions> and BEFORE <management>.