SE Please...

[Lorie]

let us be able to use the Velveteen Cowl to glamorize.

[Felis]

let us be able to use the Velveteen Cowl to glamorize.

You can do it.

[Lorie]

The base and appearance item must both be of the same type.

This means that both items have to use the same equipment slot, the exception to this rule is equipment that uses multiple slots (i.e: cowls)
To use Glamors on an equipment with multiple slots, the appearance item must be contained within the equipment slots of the base item. This means that a cowl can take on the appearance of a robe, but a robe cannot take on the appearance of a cowl. In the former example, the character will appear as if they are not wearing any headgear.
Right now level 50 mage gear is separate a head and body.

[Alukah]

They gave an answer not so long ago, it was more or less a generic "it's hard to do but we're looking into it".

[Lorie]

Thanks, must have missed that. Can't hurt to ask. ;P