There is a way do it programmatic, but it falls into the advanced Slick-C programming category, and it's not very well documented part in the Slick-C programming guide (if at all). If you look in macros\setupext.e, you'll see how a lot of file extension settings are set. For the menus, in the function _extmenu_form_update_settings on line 3856 you see:
int index=find_index('def-menu-'ext,MISC_TYPE);
_str menu_name=real_menu_name(_menu_list.p_text,'');
_str sel_menu_name=real_menu_name(_selection_menu_list.p_text,'S');
if (index) {
if (menu_name=='' && sel_menu_name=='') {
delete_name(index);
} else {
set_name_info(index, menu_name','sel_menu_name);
}
}else{
if (menu_name!='' || sel_menu_name!='') {
index=insert_name('def-menu-'ext,MISC_TYPE,menu_name','sel_menu_name);
}
}
where ext is the name of the extension and menu_name and sel_menu_name are the name of the menu resources.
It's not a lot of code, but it can mess up your state file pretty quickly if you use improperly, so I'll add the standard warning of make a backup all your configuration files, use at your own risk, beware of dogs, etc...