XL Axiata today announced on its site that it now supports carrier billing for Windows Phone Store. XL subscribers will no longer need to have a credit card to purchase many apps or games for their Windows Phone devices as they can pay using their phone credits and this works for both postpaid and prepaid subscribers.

Of course, the Store has to be the Indonesian Windows Phone Store, which means that there’s a bit of a trade off. Some apps, such as Mehdoh, arguably the best Twitter app for Windows Phone at the moment, are not available on the Indonesian store due to unexplainable reasons.

In any case, for postpaid subscribers, purchases will be included in their next phone bill while prepaid subscribers will have their purchases credited directly from their current phone credit balance. This means prepaid subscribers will have to make sure that they have enough balance in their account before they can make any purchase on the store.

Purchases can be made directly from the phone or through the Indonesian Windows Phone Store website. If it’s done from the website, you’ll need to log in first and make sure that the account is associated with the Indonesian store. Otherwise you’ll need to create a different account for the Indonesian store. Those who use a non Indonesian store account will have to reset their phone to factory setting and link their new account to the Indonesian store before proceeding.

According to XL, if you change your XL phone number to another XL number for any reason, the system will need at least 24 hours to adjust before you can begin purchasing again if you use Windows Phone 7.5 or 7.8 but 48 hours for Windows Phone 8. XL did not provide an explanation as to why it takes longer for WP8.

You can purchase up to Rp 200,000 worth of apps per month using carrier billing and up to Rp 103,540 per app. Purchases can be made when phone is connected to XL’s cellular network or over WiFi with an XL sim card present in the phone.

We’ve contacted XL Axiata for further information of the system and will post an update once we have it.

[Update] We just received an invitation to a press event regarding XL’s carrier billing for Windows Phone Store which will be held on Tuesday, 18 December. We expect to have more information then.