Piwik "Analytics": How to setup so it is served by ISPConfig?

[tester321]

I just followed another amazing "How To" on HowToForge here to install piwik.

I am wondering what changes would be necessary to have the piwik site served by ISPConfig2?

Why? I would like to use the self-signed SSL Certificate that you generate for accessing ISPConfig2 control panel (i.e., https://example.com:81) to also securely access/login to my piwik instance ... rather than to have it as cleartext and under the general webserver. (In my case Drupal multisite).

So that it would be, for example, https://example.com:81/piwik

Would it be as simple as:
1) Installing piwik to /home/admispconfig/web
2) Increasing PHP memory limit for ISPConfig2 to 128M via /root/ispconfig/php/php.ini
??

Any downside to trying to do this?

Thanks in advance for any insight.