Game released via own online store

Hi,

I'm creating a profile for a game that isn't available through stores like Steam, Gog etc., but (at this time) only through our own online store.

I am a bit confused because in the drop-down list I don't see any option like that and this field is mandatory. On the other hand I've seen some other games that in their profiles unde Game released show links to their own websites / stores.

Could anyone give me a hint if that's possible / how? Maybe I'm just missing something obvious

Thanks

A.