I've previously applied to use an auto-renewing subscription for a business app, and was rejected (I've seen reports from others that this has been the case well). Even though the guidelines list the 'business' usage is acceptable, Apple are clearly aiming them at periodicals only.
There are other issues with them to consider as well.
The way I handle it at the moment is by using multiple in-app purchases for various time periods (1 month / 3 months / 12 months etc), hold an expiry date on the device and check that on each app launch. When it has passed, the users are then presented with a re-purchase screen. They can also purchase multiple time-packs which further extends the expiry date.