Dave,
Here ya go.....
{
    @lines = grep { !/^\s*options\s*hisax/ } @lines;
    my $hisax_alias = "alias char-major-43 hisax";
    unless (exists $lines{$hisax_alias})
    {
        push @lines, $hisax_alias;
    }
    my $hisax = db_get_prop($confref, 'isdn', 'HisaxOptions') || "";
    my $type = db_get_prop($confref, 'isdn', 'Type') || "";
    my $protocol = db_get_prop($confref, 'isdn', 'Protocol') || "";
    if ($type)
    {
        $hisax .= " type=$type";
    }
    if ($protocol)
    {
        $hisax .= " protocol=$protocol";
    }
    if ($hisax)
    {
        push @lines, "options hisax $hisax";
    }
    "";
}
HTH
-jeff