Making php work on html file - could work with powerCMS?

Hi,

Could I have your opinion on this?

I will probably have to build a CMS site for one of the site I manage. The problem is, the main page contents were made in htm format, but shopping sites are in php format.
I know the fastest way is just re-save htm files into php files, but rather not to reset SEO contents.

So I just found out there's a way to make php work on htm/html file using .htaccess file, which goes something like;

AddType application/x-httpd-php .php .html .htm

I'm wondering if this trick could cheat PowerCMS (as php code functions on html/htm files with this .htaccess control) , so I don't have to change the file format to php, or it is crucial that file extension is .php?

Or you could create 301 redirects (answer.py?hl=en&answer=93633) and point the htm to the 'new' php page which automatically inherits the SEO value of the original page

Power CMS Wont apply the code to a file using the .html extension. It can only be applied to files that have the .php extension, in order to add power CMS to the page, the page extension must be .php.

301 redirects would be a good idea, or you could rename the file to use the php extension, then rename it back to the .html extension after adding power CMS to it.