"Using a scroll is basically like casting a spell."
"Spell trigger activation is similar to spell completion"
The share spell ability does not say :when you 'basically' cast a spell, or when you do things that are 'similar' to casting spells on yourself. Magic items that cast spells are not like virtual feats....reading it the way you are is no different then saying that since I can use UMD to cast a 2nd level scroll, then I have the prerequisite for PrC X.
If I use a spell from any item, its no different then casting it myself? It's explicitly different. Similar to, effectively, and basically the same are close enough for for 'virtual feats' because the rules say it is.
I think the fact that they even point out spell-like abilities as not working is pretty telling. A spell-like-ability is pretty much THE closest thing to casting an actual spell as you can get without it being the same thing. And it doesn't work with share spells. So my innate magical ability is not close enough to my class spells to work? But some item someone else created that I bought at the store that casts magic that I don't even know how to use myself IS close enough enough? I don't think that is RAW at all.
