.htaccess or php.ini

[interactive gun]

Crud, I posted this message on the php community (wrong area), so don't get mad at me, please... (as this is more an .htaccess/php.ini debate I am having with myself and the rest of the world.

Has anyone ever used cybersource gateway on a shared linux environment? There is one step completely frustrating here, and my host says it is able to be completed using .htaccess rather than the php.ini file, but I can't find anything to support this. The documentation states:
3. Copy phpN_cybersource.so into the PHP extension directory, where N is:
4 if your PHP version is 4.x.x or
5 if your PHP version is 5.0.0.
If you do not know where the PHP extension directory is, look inside php.ini
and search for "extension_dir". The value it is set to is the PHP extension
directory. If you do not already have "extension_dir" set to an explicit
directory:
a. Create an extension directory (outside of the client installation
directory).
b. Set "extension_dir" to that directory.
c. Copy the phpN_cybersource.so file to that directory location.
4. In php.ini, look for the section "Dynamic Extensions", and add the following
line anywhere before the next section:

extension=cybersource.so

and then, save your change.