Can't modify php.ini - other ways of getting email to work?

[E2E]

Hi there, I hope someone can help me out with this: Turns out (Windows) emails aren't being sent from our forum b/c the sendmail_from setting in the php.ini file is blank (this was determined by a combination of the Admin CP Diagnostics tool and help from the folks over at vBulletin.com). However, the host company won't change or let us change this file -- when we asked them about it we got the following response:

The php.ini file is on the server and controls php settings for the
server. You do not have access to this file. The link that was given
contains the code you need to create on a new page for sending email.
It is not used on the php.ini file. Use the sample code on a new php
page and modify the required sections.

"The link" mentioned in that quote is as follows: http://www.brinkster.com/Kb/Kb.asp?kb=107593, but newbie that I am I'm quite stuck as to what to do with the code therein. I'm assuming I don't -really- want to add it to an entirely new page -- but is there a certain vBulletin file I can add this to (or some -other- workaround I can use) to make email work despite our hobbled and apparently inaccessible php.ini file? The folks over at vBulletin were as helpful as they could be but pointed out that modifying the actual vB files fell into the vBulletin.org bailiwick, so...here I am! Thanks very much to anybody who might take a stab at helping with this =)