EAI Siebel Adapter Query using custom Business service

Dear Team,

I am trying to call EAI Siebel query BS in custom BS,

Parent-Child -->Parent Value Opportunity. Name and child is Opportunity Attachment. Attachment Classificatio.

below script, fetches child records  and give specific attachment IO instance as out put.

But var searchSpec = '[Opportunity.Name]= '"+[sOpty]+"' AND [Opportunity Attachment.Attachment Classification]= '"+[LOVText]"''; is validating.

Could you please advice how to correct this

function Service_PreInvokeMethod (MethodName, Inputs, Outputs)

{

if (MethodName == "Run" )

{

     var EAIService = TheApplication().GetService("EAI Siebel Adapter");

     var EAIin:PropertySet = TheApplication().NewPropertySet();

var EAIOut:PropertySet = TheApplication().NewPropertySet();

     var sOpty = EAIin.GetProperty("Oppty")

     var sDocument  = EAIin.GetProperty("Document");