Testing apache1.3 and apache2 in parallel with PHP

[Adam Kessel <ajkessel@debian.org>]

Our web-hosting service is still on apache1.3, but we've decide it's 
finally time to switch to apache2.

We would like to have both apache daemons running in parallel for a 
while to test out the setup. I have apache1.3 still listening on port 
80; apache2 listens on a different port for testing purposes.

Several users use PHP. By default, PHP is disabled. The user enables it 
on a per-directory basis using php_flag engine on.

I understand php_flag is not supported in apache2, and thus it won't 
serve content from any directory where that instruction is in the 
.htaccess file. I haven't been able to figure out how to duplicate the 
setup we have with apache2--namely, PHP disabled by default, by 
overriden on a per-directory basis. I've tried php_value engine 1, but 
that doesn't seem to work. In any event, I'm concerned anything I do to 
make the htaccess files compatible with apache2 will break compatibility 
with apache1.3, so I won't be able to have everything running in 
parallel for testing.

Two questions:

(1) How do disable PHP globally but enable per-directory in .htaccess 
for apache2?
(2) Any way to do #1 that will allow things to continue to work as 
before in apache1.3?

Thanks in advance for any tips.

Adam