Malformed SOAP messages from WebServiceFactory??

Hi all,

I am trying out some of the WSDL handling functionality of mozilla/firefox 
and I have found something a bit strange.

I get that a SOAP header is optional within an envelope but the soap 
messages generated look like this:

<env:Envelope
    xmlns:env="http://schemas.xmlsoap.org/soap/envelope/"
    xmlns:enc="http://schemas.xmlsoap.org/soap/encoding/"
.....
.....
<env:Header/>
<env:Body>
...
...
</env:Body>
</env:Envelope>

Is the <env:Header/> line valid? If so does this apply to all versions of 
SOAP? I have tried searching for this, but the major search engines ignore 
punctuation so i just get loads of hits like <SOAP-ENV:Header> - and there 
are a LOT of them! I wouldn't ask except that some services I am trying fail 
to produce any output with this line left in, but if I send the exact same 
message WITHOUT the header line, it works! (I use the Firefox extension 
Tamper Data to do this - VERY handy!)

Cheers,

Milamber³