Using multiple versions of lilypond

[Antonio PALAMA']

1.6.2 is installed and, as expected, some of the features that I had
available with previous versions do not work any more.
I would like to do some debugging in this field and the first
problem I come across is how to have multiple versions of
lilypond installed and how to switch among them.
I would like to stay with the binary sistributions (Debian)
of 1.2.17, 1.4.12 and 1.6.XX since most of my problems
are related to how LateX processes the .tex file produced
by lilypond, but having the most recent unstable version
available could probably be useful too.
And, yes, I use lilypond as a standalone program and write
my own envelope files for LateX; ly2dvi is not flexible
enough for the kind of typesetting i do.
Any pointer appreciated.
Thank you for your help.

Antonio