Digital ATIS enroute option

[Fluke]

Requesting digital ATIS's my aircraft has an arrival, departure and enroute option.
The enroute selection is very useful for bringing up current conditions at airports close to your destination or in the area you are overflying.
The trouble is it does not work for very many airports and I don't know where to look to see if the service is available and what airports will be included. ( it is a bit like a 24hr volmet)

LOWW Vienna works well giving all the close by German and Swiss airports.
My question is other than my ACARS ATIS request being rejected how do I know is the enroute data is available?

[jaja]

On the aproach plate, there will be a "D" with the ATIS frq.

That indicates that digital ATIS is available.

[sleeve of wizard]

basically anywhere that has the vhf enroute VOLMET, EGLL, EDDF, LOWW, OBBI the list goes on, give that a try