This is a script I was given a couple of years ago (I think by @bford ) that has served me very well.
Dim MySequencer as xpSequencer = nothing
MySequencer = Engine.Sequencer
Dim MyTakeItem as xpTakeItem = nothing
MySequencer.GetTakeItemByID(1235, MyTakeItem)
MyTakeItem.Execute()
Where take item 1235 was a transition we use between lower thirds.
This is contained in a script event in a scene director. I play it on a layer above my lower thirds so they don't conflict.
#XPression