Using non-default compiler to build PPA package

Hi

What is the simplest way to change the compiler used when creating binary package in PPA?

I package an application which doesn't work properly when build with g++-4.2. Unfortunately, that is the default compiler in Hardy. I have tried to avoid it by using
      Build-Depends: g++ (= 4.1) | g++ (>= 4.3)

But this has no effect:
      Checking for already installed source dependencies...
      g++: non-matching version installed (4:4.2.3-1ubuntu6 ! = 4.1)
      g++: would have to downgrade!
      g++: already installed (4:4.2.3-1ubuntu6 >= 4.3 is satisfied)

For some reasons g++ is epoched which I didn't spotted earlier. But even if I specified the epoch in the dependecies, it would probably lead to unsatisfiable dependencies, because of downgrade is not allowed and there is nothing newer in Hardy.

So the question is: what is the easiest way to force the build install and use gcc-4.1?

The only option I see so far is to specify gcc-4.1 in Build-Depends and use it explicitly in Makefile (that is CXX=g++-4.1 instead of CXX=g++). I don't like this solution because I produce packages for all ubuntu versions, so I would have to put an exception in the hardy process and that looks to me as a poor practice :-) So if anyone has better, universal solution, I'll be glad to adopt it...