Missing Internal Command cm_DirBranchSel in TC 7.50 ?

[NewUser]

I tried to add a new button to the toolbar for the Ctrl+Shift+B command, which works correctly - it shows shows branch view of only the selected dirs files. However, I could not find the cm_DirBranchSel internal comand for this shortcut.
Moreover, When I specified the cm_DirBranch for the filter, the only command that matched was cm_DirBranch.
Is there any work-around for this problem, how can I either
add a new button for this command or
redefine "Ctrl+Shift+B" to say "Ctrl+F1"?

[ghisler(Author)]

cm_DirBranchSel is new to TC 7.55. Shift is just ignored by TC 7.50a, so you get the same as with cm_DirBranch.