Trying to change Opportunity SalesStage with WebServices Update

Question

I have successfully updated a custom field in an opportunity, but when I try to update the SalesStage to "Closed/Won", I get the error: Cannot find entry ''Closed/Won'' in the bounded picklist for the field 'Sales Stage - Translation' in integration component 'Opportunity'(SBL-EAI-04401).
Closed/Won is a valid choice in the dropdown list, but I am wondering if I need to update with a value or object that is different that the display term.
Here is the C#/.Net code I use that references the opportunity.cs created from the WSDL for our schema.
WebServices.Opportunity.Opportunity webService = new WebServices.Opportunity.Opportunity();
// WebServices.Opportunity.Opportunity1 oppUpdate = queryOutput.ListOfOpportunity[0];
WebServices.Opportunity.OpportunityWS_OpportunityUpdate_Input updateInput = new WebServices.Opportunity.OpportunityWS_OpportunityUpdate_Input();
WebServices.Opportunity.Opportunity1 updateOpp = new WebServices.Opportunity.Opportunity1();
initializeStrings(updateOpp);
updateOpp.OpportunityId = opportunityID;
updateOpp.SalesStage = "Closed/Won";
updateInput.ListOfOpportunity = new WebServices.Opportunity.Opportunity1[] { updateOpp };
          WebServices.Opportunity.OpportunityWS_OpportunityUpdate_Output updateOutput = null;
          lock (requestLock) {
               prepRequest(webService);
               updateOutput = webService.OpportunityUpdate(updateInput);
               lastRequestEnd = DateTime.Now;
// I am not sure what comes back from this update query
          if (updateOutput != null && updateOutput.ListOfOpportunity != null && updateOutput.ListOfOpportunity.Length > 0)
               result = true;
I'd appreciate your help if you know what to do or have an example to share.

Answer 1

Thanks for your response.
We have 8 values of SalesStage defined. Stage1 through Stage 6 are custom stages added to the built-in Closed/Won and Closed Lost stages.
I think I see what you are saying is that if the SalesProcess and SalesProcessId are not set, the web service API does not know what picklist of SalesStage values to refer to. Is that right? I've changed my code to first read the opportunity and get the values in those 2 fields (SalesProcess and SalesProcessId), then set these values in the update record along with the SalesStage and run the update. I still get the same error that Closed/Won is not in the picklist for 'Sales Stage - Translation'. Is the 'Translation' an indication of the mapping to a sales process?
It appears that the SalesStageID also changes with each stage selected. Do I have to set that as well or will it be changed by the server when I change SalesStage? If so, I will have to do some debugging to find the values of the SalesStageID associated with each SalesStage.