Adding custom HTTP headers to a webservice breaks soap operations

Steps to reproduce:
1. Add an ASP.NET 2.0 webservice to a flex 3.5.0 project (in Flash Builder) using "Connect to webservice"
2. In the modifiable web service class add a custom http header to the constructor (mine was ws.httpHeaders =

3. Use two or more calls to different webservice methods. Observer the results in fiddler

Actual Results:
The webservice will call all methods with the correct soap body but the http SOAPAction header will all be the same and will be the one for the first web service request.

Expected Results:
The SOAPAction header should be different for all methods.

The issue lies in sdks\3.5.0\frameworks\projects\rpc\src\mx\rpc\soap\Operation.as lines 795-797. It only sets the SOAPAction header from the wsdl if it isn't already set. For some reason the httpHeaders variable in this class has stored the SOAPAction header in addition to the custom headers. I couldn't find where this was being set but it was not set when custom httpheaders were not used - in this case httpHeaders was always null.

Workaround (if any):
Only way for this to work is to not add custom http headers, and this is not an acceptable workaround.