[web2py] Linking the view button on a grid to the correct table for a multi-table query

[simon]

I have a grid where I want to show all payments for a customer. It is 
driven by this query:

       ((db.payment.id > 0) & (db.payment.salesorder==db.salesorder.id) & 
(db.salesorder.customer == customerid))

It shows the correct rows. However the view button links to the salesorder 
and I want it to show the payment. Is this possible?

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