How to Read Catalog im****t Response message using biztalk

Hi,
I am trying to im****t catalog using biztalk server 2006. I already 
accomplished the im****t part by using the commerce server catalog adapter 
with a one way send ****t.

Because I need to comfirm the im****t is successed completed. So I need to 
read the Im****t response message from commerce server.

But I am encountered problem with the reading of the Catalog im****t
response 
message.

In the biztalk administrator events,it shows im****t process start event
and 
im****t complete event. but after that, there is a XLANG error come up says

that there is a inner exception:Received unexpected message type 
'CommerceServerCatalogIm****tResponse' does not match expected type 
'MSCommerceCatalogCollection2'.

It seems the CommerceServer Catalog Adapter does not recognize the
response 
message.But I did checked the help do***ent for commerce server.According
to 
the help, the response message should follow the DefaultCatalog.xsd 
schema.And I also debuged the Orchestration, it show the returned message
did 
match the DefaultCatalog.xsd.

Really have no clue why adapter is not recognizing the response message.
Can anybody help me?