[Nagiosplug-help] get http and xml

[Hotfoot]

Hi All,

I'm trying to post an xml string, and checking expected output... my 
problem is I need the request to follow this guideline:
*"Each XML request sent as a HTTP POST must have a content type of 
text/xml"*
How can I change my posted content type from "Content-Type: 
text/plain;charset=ISO-8859-1" which seems to
be the Nagios default to the above text/xml

Any clues greatly appreciated.
Regards
Hotfoot