Shadow Adept in Hiding - How?

[Miyu]

I need some advice concerning the shadow weave rules and fluff concerning a powerfull antagonist in my current campaign, a wizard/shadow adept.

The main problem is, the informations about the shadow weave and the rules concerning it are not only vague but also controversial (which fits shar I suppose)

The NPC is not only hiding amongst the population of a smaller city but also has a medium rank in the local wizard guild. Problem is, some (official) sources say, you'll lose the access to the weave the moment you take the shadow weave magic feat. Other (official) sources say, your access to the weave gets gradually smaller (which makes at least a tad more sense). If the first applies and the wizard is forced to sap all power from the shadow weave: How to avoid the next mage coming across this wizard casting a spell, saying "hey, nice spell, but thanks to my freaky divination skills i can see it isnt there, therefore shadow magic, therefore DISINTIGRATE"

While as a DM I could say "f*ck you, my house my rules" I would like to have a handy (and preferably logical) explanation how this NPC avoids detection as an ace in the hole.

Any Hints?

[Yechezkiel]

A stand-in caster minion with some magical (or non-magical) disguises?

Does a Shadow Weaver cast spells from items (scrolls, wands, etc.) as normal (do they appear as "of the Weave")?

[Miyu]

Thats the question, how can he (non)magically disguise himself to a point, where a divination mage (at least someone of a lower level) would recognize him as a normal weave user.

Items are only specificly mentioned concerning own items (which will be shadow weave items) and such with spells from the light descriptor and spell completion or spell trigger activation method (which will fail to work, as a shadow weave user cannot use light spell in general)

The Insidious Magic feat makes it harder for normal weave divination spells to detect shadow magic spells, however, the spell is hidden in this case, not carmouflaged.

Also I'm not sure whether regular spells without the darkness descriptor cast by a shadow weave user would be discovered to be a shadow magic spell anyway. As I said, the informations are vague at best.

[Yechezkiel]

I say look for a less game mechanical explination and a more npc-rp one.

Could the Shadow Weave user be bribing/extorting/blackmailing the Diviner of the guild? Could he be corrupting/converting him?

I agree the Shadow Weave stuff is vague from the feats/rules, maybe someone with more knowledge from the novels and other fluff would know better.