Small fix in POST XML parser

git-svn-id: http://svn.zoo-project.org/svn/trunk@472 4b6b6ad6-68b3-4dcc-9231-bd9b83bc5dc3
Fix issue still kept in previous commit

git-svn-id: http://svn.zoo-project.org/svn/trunk@473 4b6b6ad6-68b3-4dcc-9231-bd9b83bc5dc3