Ok it doesn't work the way I want it.
Jojo86, I have done that a couple times and I get buttons (in all rows of one column) with the same link to the same form I want to open when I change to form view. But that's not what I want. All right, maybe I need to explain what I see when I open the form in design view. I only see the header and the footer and one row called Detail, but I don't see any of my 6000 entries. Because I've created the form with the form wizard and the source is a query. So how am I supposed to add a button to an entry I want to if I don't see it?!
And again if I do it thw way jojo86 suggested I get a whole column with the same button to the same form. And if I want to change, for example, the link of the sceond row, and I change to formview and click on the button, it will open two forms (the one from the first and the one from the second row).
Sorry, but I don't get it.