Unable to send files to SOAP Web Service in 3.6

I have a test project that tests a Windows SOAP Web Service.
One of the methods is called AddItemImage which takes an image as a parameter (and some other un-imporant parameters).
I have a test method that calls this method. It worked perfectly in soapUI Pro 3.5.1.
When I upgraded to soapUI Pro 3.6 it stopped working. I get a "HTTP 400 - Bad request" every time I call the method.
This is exactly the same project that runs perfectly in soapUI Pro 3.5.1.

After analyzing the traffic in Microsoft Network Monitor 3.4 I get these results:
soapUI Pro 3.5.1:
- Node: XmlElement:<api:AddItemImage>
+ STag: <api:AddItemImage>
+ Element: XmlElement:<api:requestId> - 43008
- Element: XmlElement:<api:imageData>
+ STag: <api:imageData>
Content: /9j/4AAQSkZJRgABAQAAAQABAAD//gA7Q1JFQVRPUjogZ2QtanBlZyB2MS4wICh1c2luZyBJSkcgSlBFRyB2NjIpLCBxdWFsaXR5ID0gNzUK/9sAQwAIBgYHBgUIBwcHCQkICgwUDQwLCwwZEhMPFB0aHx4dGhwcICQuJyAiLCMcHCg3KSwwMTQ0NB8nOT04MjwuMzQy/9sAQwEJCQkMCwwYDQ0YMiEcITIyMjIyMjIyMjIyMjIyMjIyMj
ETag:

soapUI Pro 3.6:
- Node: XmlElement:<api:AddItemImage>
+ STag: <api:AddItemImage>
+ Element: XmlElement:<api:requestId> - 43011
+ Element: XmlElement:<api:imageData> - cid:kattungar.jpg
"kattungar.jpg" is the filename of the file I was trying to send to the Web Service.
It looks like soapUI Pro 3.5.1 sends the data of the file and soapUI Pro 3.6 just sends the filename to the webservice.

I have tried the latest daily build (soapui-pro-daily-2010-09-15-[1], Build Date 2010/09/15 02:23) with the same result.

Thanks
/nils