Mounting inside a 3.5 bay

So the USB/UIRT is 2.4 in in width, which is too small for a 3.5 bay door on a case. This strikes me as being an ideal place to put this item. Has anybody done this, and if so, how did you do it? e.g., additional plastic, some mounting door, etc?
Reason I ask is that I'm thinking of buying a black shuttle case, and it will have an unused 3.5 bay that might work well with this. Thanks.
Reason I ask is that I'm thinking of buying a black shuttle case, and it will have an unused 3.5 bay that might work well with this. Thanks.