Logging Errors to a File

I am using an Apache webserver w/ PHP provided by a hosting company & I can't seem to get PHP errors logged to a file. From reading the docs, my understanding is that I need to set error_log to the name of a file & set log_errors to on in the php.ini file (.htaccess, in my case). Is this correct? I tried setting these two parameters in my .htaccess file. When I do a phpinfo() I see that error_log has been set, but the error_log value doesn't seem to change. It remains off no matter what I do. I'm wondering whether the hosting company may not allow this value to be overridden. Does this make sense? Any other thoughts? -- JR