mod_proxy_ajp.so: Undefined symbol "proxy_module"

[Al]

In my quest to get apache 2.2 to play nice with tomcat 5.5, I started
out with the following command.

# /usr/local/sbin/portupgrade -RrN -m 'WITH_MPM=worker
-DWITH_PROXY_MODULES' /usr/ports/www/apache22

After getting around fixing portupgrade issues, I was finally able to
rebuild everything without errors.  However, when trying to start
apache, I get the following error:

httpd: Syntax error on line 104 of /usr/local/etc/apache22/httpd.conf:
Cannot load /usr/local/libexec/apache22/mod_proxy_ajp.so into server:
/usr/local/libexec/apache22/mod_proxy_ajp.so: Undefined symbol
"proxy_module"

Clearly, I missed something.  Any clues would be appreciated.

Running FreeBSD 5.4


-Al