Singapore Airlines KrisFlyer - Advanced seat assignment in Raffles

I did a forum search, but couldn't find any info for this. I am traveling on a biz class award which I redeemed online. I then reserved a seat via the website which was smooth and easy (22D). My wife purchased an economy ticket from our travel agent and we upgraded her to biz with miles. When I look at the website for her the reservation code is not associated with her so I can't make an online seat reservation for her. We are traveling with our 20 month old daughter so we will spare most biz travelers and fly on the lower deck of the 747. I am trying to book my wife on the aisle seat as I figure no one will book the middle seat and we can have our daughter there.

How do I go about getting her seat assigned in advance? Phone to Krisflyer?, SQ? or ?

Call SQ reservations. They should be able to reserve your wife's seat for you.
I have done what you are trying to do when my kids were younger - no problem.
Just be prepared if the flight is completely full & someone actually sits in the middle seat.

Good luck and & hope you have a nice trip. :)