I don’t believe there’s a PHP library capable of “talking” directly to exchange outside of pop/imap so that wouldn’t be an option, but we’ll research this more to see if it’s possible.
In version 2 (currently in development) there’s an API for doing this. One problem though is that even if you programatically enter the requests any follow up emails will be very hard to map correctly without HelpSpot checking the box itself.
A simpler option would be to use a mail alias acocunt to route the emails to an outside email account, like gmail. You can securely connect (actually you must securely connect) to gmail so it’s relatively safe. Then HelpSpot will just use gmail to pull in email though it will still send the “from” as your corporate account so it won’t appear that you’re using gmail.