Is it the VDN name that you're not seeing when the coverage is set to y? If so, this is apparently how it is supposed to work. I've copied below a note from the Call Center Call Vectoring and EAS Guide. Instead of routing directly to x7792 would routing to a phantom extension that covers to 7792 work for you?
Note from Avaya Doc:
1. When the with coverage option is set to y, the call is removed from vector processing when the route-to step is
reached, regardless of facility or remote switch availability. The call is taken out of any split queue, and any
feedback, such as music or ringback, is removed, even if the destination is not available. If the call is subsequently
rejected by the receiving switch vector, subsequent call treatment is defined by the rejection command (either busy
or forced disconnect). The call is treated as though the destination is directly dialed (see footnote 3 for related
information). This includes coverage, forwarding, treatments for calls that cannot be completed (busy reorder, and
intercept) and displays. The answering station sees only caller name and number, unless the Display VDN for
route-to DACS option is enabled (for more information, see Displaying VDN names for vector-initiated DACs on
page 663). A call routed with an adjunct routing link command is treated the same way as a call that is routed using a route-to with coverage y command.
3. A call that routes to a VDN using the route-to number with cov = y unconditionally command behaves
like a directly- dialed call instead of a VDN call. Therefore, the terminating stations display only shows the
originating station information and does not show the VDN information (for other types of VDN calls, the terminating
station would see the VDN name