With the GPS150 / GNC250, you just selected the chosen user waypoint and it displayed brg/dist from that waypoint continuously - leaving you free to use the DCT feature for other purposes. Or you could let the automated 'nearest' function give you brg/dist from the nearest category of feature. You didn't need to tie the DCT function up with brg/dist from homeplate. Simples indeed.
But, as far as I can ascertain, that feature is missing from the Aera series. Present position only shows brg/dist from the nearest category of feature you've told it (e.g. from the nearest aerodrome) or, by default, from Garmin's idea of the nearest significant feature whether it's a town, aerodrome or whatever.
A simple 'nearest' / 'user' software upgrade would solve the issue. I really hate having to fight stupid automation!