Don´t know if that is possible only with mapkeys...
But I have a solution that may work for your specific case if you only need to select the first result found.
Replace the line
mapkey(continued) ~ Select `selspecdlg0` `ResultList` 1 `7:52:`
with
mapkey(continued) ~ Select `selspecdlg0` `ResultList` -1; \
This will select all results found (similar to Control+A), but if only one result is expected, then only the first will remain selected.
The second step is to guarantee that the first result is the first in the tree, and there´s a option for that: options->sort by...-> Item Id
Not sure that it will work as you intend, but try the code I attached.
Jose