What option must I chose if I wish to get Nalia kidnapped? Okay, that might seem like a odd question, but I'm looking for adventure! So, must I (I'm playing a male character now) marry her, after beating the keep, or must I let her join up with my party? What should I say?

*clueless*

Let her join your party.

SPOILER
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After a while a messenger will show up telling about her father's burial. Go to the graveyard and let Nalia talk to Isea. A couple of days later (I think) Isea will kidnap her.

Thanks! I'll do just that! :)

I'd be very cautious while doing this. Ask yourself, "Do I ever want to see her again?" I've done all you are supposed to do to get her back (If you follow the directions everyone gives you, it is very straight forward) and they still won't hand her back.

Did you: SPOILER
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-talk to the smuggler who directs you to Dirth?
-found the slaver documents
-found the financial documents

and went to Isaea's superior and tell him:
-you have a witness
-you have found slaver documents
-you have found his financial documents

After a 'movie' Nalia should appear and ask to join you again.

I had done all of these things, but then dropped the old financial statements, so I wasn't given the opportunity to declare them.