I don't know if this is the best way to go about this, but you can configure Cron to run on a regular basis to run a small script that will delete the old files in the /var/log/apache2 directory. Here are the steps to do that.

1. Create a file named ApacheLogRotateDelete in the /etc/cron.monthly directory.

2. Paste the following into that ApacheLogRotateDelete file:
#!/bin/bash
find /var/log/apache2/* -mtime +5 -exec rm {} \;

3. Change the rights on /etc/cron.monthly/ApacheLogRotateDelete
chmod 755 /etc/cron.monthly/ApacheLogRotateDelete

4. Restart cron
cd /etc/init.d
./cron restart

NOTES:
Which files to delete:
The "find /var/log/apache2/* -mtime +5 -exec rm {} \;" line causes all files greater than 5 days old to be deleted. You can change the number of days by changing +5 to +10 days, or +x for some other number of days.

How often to run the delete script:
The instructions above cause the ApacheLogRotateDelete script to run every Month. You can have that run daily or weekly by using the cron.daily or cron.weekly directory.