We have a tradition in my part of Spain of using "toasted" vermicelli. Only thing is that it's a little thicker (not much more) and much shorter than the Seviyan the recipe calls for and it isn't sold ready toasted, that's something we do ourselves.
This recipe shows an example of how it is done
http://lasrecetasdelmarquesdemuchaba...rossejats.html
(Rather than actually being roasted the vermicelli is fried in a large pan - or wok - with a few tablespoons of good olive oil).

I'd be cautious about adding standard vermicelli along with the water in your recipe. If you can't find the pre toasted kind perhaps you could fry it with the other ingredients for a few minutes before adding the water (let the colour change a bit at least). Since the pre-toasting/frying makes such a big difference to the Spanish pasta dishes, I can't help but suspect that having toasted vermicelli will make a difference over just boiling standard vermicelli in the dish you want to recreate.
Hope it works out!