How to interpolate Variables in GlobalSub?

[Detlev Ehmann <ehmann@wws.de>]

Hi,
I need some of the minivend values like price etc. for an external CGI.
So I defined a GlobalSub in minivend.cfg like this:

sub exec_cardpl
{
my $preis=$_[0];
my $ident=$_[1];
my $line;
open(OUTHANDLE, "> transe.txt") or die "Kann Datei nicht oeffnen\n";
@lines=`./WSender -f wsenderini -p $preis -i $ident`;
print OUTHANDLE "$preis";
print OUTHANDLE "$ident";
close OUTHANDLE;
}

I call the Sub from minivend.cfg with: 
[perl sub] 
        exec_cardpl ("[scratch preis]","[value mv_session_id]")
[/perl]      

But the two Variables $preis and $ident are not translated in my Outhandle-File.
Why?
Thank you for help.
	Detlev Ehmann