MS-Access

Hi.
I have a Problem with a view of Postgres in Access. I defined some rules to edit 2 of the fields of the view. In
pgAdminwith update it works fine. 
In Access I get a write-conflict with the option to cancel or put in clipboard.

Why is that?

I searched the internet and found some text telling me to put in a timestamp-field in that table. What should that do?
Ihave several timestamp-fields in my tables and access behaves not different. 
I think they mean a timestampfield that is changed by the postgres-server each time the data changes.
One document in the MS-Knowledge base said, that the primary key and that timestampfield have to have an unique index
(createunique index to auftraege (auftragsnr,tsfield);) 
And the really want to believe me, access is intelligent enough to realize that unique index and to use it instead of
comparingeach field? 

If that is so, do I have to create such an index-field for my view or is it enough to have auftragsnr and tsfield from
auftraegein my view. 

How do I create a rule, that changes the timestamp-field each time a table-entry is changed?
The following does not work, because it is recursive:

create rule test on update to auftraege do update auftraege set tsfield = current_timestamp where auftragsnr =
new.auftragsnr;


Help!

Aksels