'Title' argument with language attribute in REX

Hi,

i am trying to achief the following goal with postprocessing via REX:
Change 'title' argument with specific language attributes.

Here is an example from my grabbed xmltv-file:

<programme start="20181105080000 +0100" stop="20181105090000 +0100" channel="National Geo HD (PL)">
<title lang="pl">Wielkie konstrukcje: Olbrzymie mosty</title>
<title lang="en">Megabridges</title>
<sub-title lang="pl">Grecja</sub-title>
<sub-title lang="en">Greece</sub-title>
<desc lang="pl">x y z</desc>
<date>2005</date>
<category lang="pl">Film Dokumentalny</category>
<country lang="pl">USA</country>
<episode-num system="onscreen">E2</episode-num>
<rating>
<value>+12</value>
</rating>
</programme>

What i would like to achief is the exchange of title argument so that i get title lang="en" as the main
title argument or at last attach the title with attribute lang="en" to the existing main title argument.

I have no idea how to target the language attributes from the title argument within the postprocessing via REX.
In the documentation of REX (Rex.config.documented) there is nothing mentioned about the language attributes.
Is this possible at all?

I am using the latest version of Webgrab+ on a Windows7 machine.
Site-ini, Config-file and the full grabbed XML-file are attached.

Anykind of help would be very much appreciated. Thanks