NetTool

I am using nettool for the first time and want to post xml content to my WSAD local Websphere Application Server. I've tried the add headers option to change the Content-Type to text/xml. The tool seems to accept the new header value for Content-Type but ignores it in the post, sending text/html as shown below:
Any help would be greatly appreciated.
Thanks,
Adam
xml input message:

<?xml version="1.0" encoding="UTF-8" ?>
<cXML payloadID="1164821594702.1640716864@xxx.com" timestamp="2006-11-29T18:33:14-23:00" version="1.2.008" xml:lang="en">
<Header>
<From>
<Credential domain="NetworkId">
<Identity>fromident</Identity>
</Credential>
</From>
<To>
<Credential domain="NetworkId">
<Identity>myreceiver</Identity>
</Credential>
</To>
<Sender>
<Credential domain="NetworkId">
<Identity>networkSender</Identity>
<SharedSecret>secret1</SharedSecret>
</Credential>
<UserAgent>agent1</UserAgent>
</Sender>
</Header>
<Request deploymentMode="test">
<PunchOutSetupRequest operation="create">
<BuyerCookie>aCookie</BuyerCookie>
<BrowserFormPost>
<URL>https://buySystem.test1.com/BuyerSystemPOOMReturnURL</URL>
</BrowserFormPost>
<SupplierSetup>
<URL>htps://localhost/mh/server/tp=dist1/ssid=1234567897865462313213564654652131321</URL>
</SupplierSetup>
<ShipTo>
<Address addressID="3100">
<Name xml:lang="en">3100</Name>
<PostalAddress>
<DeliverTo>test</DeliverTo>
<Street>1755 Steeles Ave. West</Street>
<City>Toronto</City>
<State>ON</State>
<PostalCode>M2R 3T4</PostalCode>
<Country isoCountryCode="US">US</Country>
</PostalAddress>
</Address>
</ShipTo>
</PunchOutSetupRequest>
</Request>
</cXML>

Headers as they appear in nettool after add headers
Host localhost
Content-Length 1813
Cookie
Content-Type text/xml

Response in nettool response window

HTTP/1.1 404 Not Found
Server: WebSphere Application Server/5.1
Set-Cookie: WCS_UNIQUE_ID=yZEgkshX6MDyOzjWKi%2b833LRRSc%3d%0d%0a;Path=/
Expires: Thu, 01 Dec 1994 16:00:00 GMT
Set-Cookie: WC_SESSION_ESTABLISHED=true;Path=/
Set-Cookie: WC_ACTIVESTOREDATA=%2d1%2c0;Path=/
Set-Cookie: WC_USERSESSION_-1002=%2d1002%2c%2d1%2cnull%2c%2d2000%2cnull%2cnull%2cnull%2cnull%2cnull%2cnull%2cnull%2cnull%2c%5b0%7cnull%7cnull%7cnull%7c%2d2000%5d%2cc0DTzLi27KNosEVmmZfy9Z3KN30%3d;Path=/
Cache-Control: no-cache="set-cookie,set-cookie2"
Content-Type: text/html;charset=ISO8859-1
Content-Language: en-US
Transfer-Encoding: chunked