Unless they fundamentally change something in 4.5 there, you can later add them to new generated cfg file of 4.5.
As long as you are only adding the [fltsim.XX] entries, I can't see a huge difference between 4.4 and 4.5. One that will change (or at least it should), is the description= line.

[fltsim.0]
title=Captain Sim 757-200 FSX 0
sim=cs757-200
model=PW
panel=
sound=PW
texture=delta
kb_checklists=
kb_reference=
atc_id=N675DL
atc_airline=Delta
atc_flight_number=757
ui_manufacturer=Boeing
ui_type=757-200 PW
ui_variation=Delta
ui_typerole="Commercial Airliner"
ui_createdby="Captain Sim"
description=757 Captain (757-200 Base Pack) v.4.4\n(c) 2009 Captain Sim \nwww.captainsim.com
ui_wglts=0

It could be like this: description=757 Captain (757-200 Base Pack) v.4.5\n(c) 2011 Captain Sim \nwww.captainsim.com ;)

Mark