Boot priority selection question

[JBLanteigne]

First, I have two os x instalations. One from kalyway and one from retail dvd.

 

When I boot my hdd I get the darwin loader thing, just like when I boot the kalyway dvd..

 

and I get three partitions (three? I mean.. disk utility says there are 2 so I don't know where that third one came from)

 

first one is empty,

2nd one is kalyway

3rd one is the retail install

 

and by default, my system boots into the kalyway partition.

 

I would like to know how I can change it so it automaticly boot into the 3rd one

 

Thanks.