Overriding installed lisp code from home directory?

[Rafal Kolanski <rafalk cse unsw edu au>]

Greetings,

Could someone remind me (I've looked, but nothing seems very relevant) 
what the correct procedure is for "shadowing" lisp files installed on 
the system?

Basically, I want ~/.sawfish/lisp/wm/placement/smart.pl to override 
/usr/share/sawfish/1.3.5.2/lisp/sawfish/wm/placement/smart.jl when 
sawfish loads.

Can this be done at all? If so, how? I'm running 1.3.5.2

If it's possible and I find out how, I'll try add it to the FAQ.

Thanks in advance,

Rafal Kolanski.