How to install some script files to sbin?

Hello,

I want to use Module::Build with an application. This application comes with some
libraries, some files to be installed to a bin/ directory, and some files to
be installed to a sbin/ directory.

Installing stuff to lib and bin and man works. Now I want to install some
other script into sbin instead. So far my Build.PL looks like this:

 #!/usr/bin/env perl
 use strict;
 use warnings;
 use Module::Build;

 my $build = Module::Build->new(
     # stuff like dist_* ...
     script_files => [ 'myapp' ],
     sbin_files => { 'myapp_admin' => 'sbin/myapp_admin' },
 );
 $build->add_build_element('sbin');
 $build->install_base_relpaths('sbin' => 'sbin');
 $build->prefix_relpaths('site', 'sbin' => 'sbin');
 $build->prefix_relpaths('core', 'sbin' => 'sbin');
 $build->prefix_relpaths('vendor', 'sbin' => 'sbin');
 $build->create_build_script;

but it (M::B 0.35) just doesn't install myapp_admin, it doesn't mention it,
just skips.

So what am I missing here to make it respect sbin?

(Additionally, it would be nice to tell it to scan the sbin_files for POD.)