So I'm still trying to get a good hold on crafting mechanics, and I think I have most of the basics down. But I only just now noticed that my character can sacrifice a spell slot to learn one of his spells as a 2/day spell-like ability (it's a homebrewed class), because of this I'm wondering if spell-like abilities can be used for item crafting or if one has to cast the spell as... well, a spell, for purposes of crafting a magic item.
I'd be very glad if you could back up your responses with the source.
Oh, and this is not for PFS.