Update:
An article here will outline how you can submit a desktop application to the store. Unfortunately how this works is when the user downloads a Desktop Application from the store, it will load a Metro style portion and then navigate them away from the store to download. The Store will handle said transaction and compensate you accordingly based on the acquisition.
As part of the submission process, you must supply a purchase page URL
for your app. This URL is a link that sends the user directly to the
page where a customer can acquire your app with the fewest clicks
possible. This is a great feature for customers; if you provide them
with a clean and easy way to acquire your app, you’re already making a
great impression by giving them a simple and clear acquisition
experience.
![Example Image]()
When you submit a desktop app, you must supply a purchase URL for
32-bit and 64-bit systems. This URL can be the same for both.
During the app submission process, we request that you supply a URL
for users who need the x86 version of an app and one for those who
need the x64 version. For Release Preview, both URL fields are
required, and should correspond to the version of Windows that a user
is running. If the acquisition page is the same for both, we recommend
that you use the same URL in both fields. The Windows Store detects
whether a user is running the x86 or x64 version of Windows, and users
can only see apps that correspond to this version.
Essentially Microsoft will only be handling the commerce of your application; all other aspects will be handled outside of the store. The only aspect that Microsoft will directly handle is the initial commerce, with In-App purchases you might be able to have the commerce portion handled, but you'll still need to provide the information to be handled outside of the store.
Also, the current outline for a said feature in desktop applications really hasn't been covered any the documentation, perhaps as 8.1 approaches more details will be announced.
