Obtain data from drop box using lookup field.

Obtain data from drop box using lookup field.

Hi, I'm just having a bit of a issue trying to get data from a drop box in one form and recreate it in another form using a lookup field dropbox. 

Pretty much I have a add staff form which takes the first letters of the staffs first names to create a initial code in dropbox "Initials" which I then want to be shown on my add bookings form so it can be shown which staff member made (and stuffed up haha!) the bookings.

If I try make a lookup field in add bookings it will not show me the Initials field.
Are drop boxes not supported for lookup fields?
If not is there any one who has scripted this in?
Any help would be much appreciated!

Cheers.