[Groff] how to use .GETST in a figure caption?

[Anton Shterenlikht]

I want to reference some figure in the caption of
another figure. I tried:

.DS CB
.PSPIC rep-room-mises-nomesh.ps 6.0
.ds caption "Same as Fig. \"
.as caption ".GETST fig:room-mises-mesh,"\
.as caption " but with mesh not plotted for clarity.\"
.FG "\*[caption]" "" 0 fig:room-mises-nomesh
.SETR fig:room-mises-nomesh
.DE

which doesn't work, it just inserts

        .GETST fig:room-mises-mesh,

into the caption verbatim, unprocessed.
How to do this correctly?

Many thanks

Anton