SJU Abogado

Since NW is a code share of Malev, I am hoping that this is an appropriate forum for my question.

I just booked my Malev flight from AMS to BUD on the NW website (my originating flight from EWR to AMS is on CO). NW - on its website and through its phone agents - professed an inability to access MA's seat maps and assign me seats on the MA flights. When I called MA's US office, the agent told me to deal with NW, which should be able to assign a seat. That was fruitless, so I then called MA's reservations line in Hungary, and the agent told me that since I booked with NW I will not be able to get a seat assignment until I get to the airport on the date of departure.

What gives? Is there any way for me to get seat assignments before my early June flights? And if not, am I being set up for a middle seat on a MA 737 (my AMS to BUD flight is at 10:00 a.m. on a Tuesday, and my BUD to AMS flight is at 7:10 a.m. on a Friday)?

Thanks.