Hi Vitaly, 

If I'm understanding your suggestion correctly. All i need to do is to extend my custom HSPI.MPI.Operation to HS.MPI.HSPI.Operations. 

Class MC.ACO.HSPI.Operation Extends (HS.MPI.HSPI.Operations, HS.Util.Trace.Helper)

I did tested this, unfortunately i got the same error 


ERROR #6248: SOAP response is a SOAP fault: faultcode=Client
faultstring=Badly formed SOAP Message
<error xmlns="http://www.intersystems.com/HSPI">
<text>ERROR #6277: Type attribute, s01:AcoPatientSearchRequest, does not specify valid type for XML input tag: pRequest (ending at line 5 character 171).</text>

Hi Vataly, just to give a quick overview of the workflow. we receive a patient roster file in a pipe delimited text format. The file is consumed by an inbound file service, put into dedicated folder, read file using a dedicated custom record map designed base on the roster's file layout then parses the file. Once the input file is parsed it is then transformed into a standard HS Patient Search Request message (HS.Message.PatientSearchRequest). 
the standard patient search request is sent to custom HSPI MPI Operations that extends to HS.MPI.AbstractOperations to do the patient search. Depending on the result of patient search a standard (HS.Message.Patient SearchResponse)
will be sent back.

The standard HS.Message.PatientSearchRequest class is where i extended the custom class to add the Roster Effective and Term Date. The error is happening when patient search request message
is submitted to the custom HSPI MPI Operations for patient matching.