Perl5Util.subsitute() and ${X} symbolic references in the substitution pattern

In an actual Perl program, I can write a regex substitution like:

$x =~ s/abc(def)ghi(jkl)/${1}123${2}/;

This doesn't work with ORO. Instead I have to:

util.substitute("s/abc(def)ghi(jkl)/$1\\123$2/");

I am using ORO to read in legacy Perl regexes from an external source, so
getting it to work with the symbolic references would be best.

Is there a way?

-BD