What I expected to happen was...:
The selected Minecraft profile would launch and work properly when using a Minecraft install made with the old launcher
What actually happened was...:
The selected Minecraft profile launches the latest version of Minecraft.
The launcher does not attempt to load minecraft.jar from the bin folder at all.
Steps to Reproduce:
1: Click New Profile
2: check "Game Directory"
3: enter path to .minecraft in the text box
4: click Save Profile
5: Select the profile in the Profile menu
6: click Play