I read on in an another forum thread that when BtsActionMapping is used the WCF adapter tries to match the operation name with an action defined in the BtsActionMapping, and if it can’t find the Operation context property in the BTS message, it sets the whole BtsActionMapping as the action on the outgoing WCF message.
And since no orchestrations are used the Operation context property (that comes with the default binding file) is not set.
The solution is to set the action of the send port directly to http://Microsoft.Samples.BizTalk.WCF.BasicHttpSendAdapter.BasicHttpWcfServiceConsuming/IOrderProcess/Submit
//Ershad