skroutz.gr feed: size variations (Embedded XML Element)

Hi and congrats for this awesome plugin,

I’m creating a feed for greek multivendor site skroutz.gr

My shop is a jewelry shop voilakosmima.com. I’m trying to create my variable products feed (size + color) according to this page: https://developer.skroutz.gr/feedspec/#size-variation-attributes

so i can finally have a feed of this type and separate embedded feed for every product variation:

<?xml version="1.0" encoding="UTF-8"?>
<mywebstore>
   <created_at>2010-04-08 12:32</created_at>
   <products>
      <product>
        <id>322233</id>
        <name><![CDATA[Converse All Star Chuck Taylor Ox]]></name>
        <link><![CDATA[https://www.mywebstore.co.uk/product/322233]]></link>
        <image><![CDATA[https://www.mywebstore.co.uk/product/322233.jpg]]></image>
        <additionalimage><![CDATA[https://www.mywebstore.co.uk/product/322233/front.jpg]]></additionalimage>
        <category><![CDATA[Outdor > Sneakers]]></category>
        <price_with_vat>30.00</price_with_vat>
        <vat>24.00</vat>
        <manufacturer><![CDATA[Converse]]></manufacturer>
        <mpn>M7652C</mpn>
        <ean>886952780692</ean>
        <availability>Delivery 1 to 3 days</availability>
        <size>43,45</size>
        <weight>2000</weight>
        <color>White</color>
        <description>
          The Chuck Taylor All Star is one of the most iconic sneakers
          of all ages. It is a unique design with a classic and comfortable
          fit, in white color, with durable non-slip exterior rubber sole.
          It is an ideal piece for all kinds of appearances.
        </description>
        <quantity>10</quantity>
        <variations>
          <variation>
            <variationid>322233.43</variationid>
            <link><![CDATA[https://www.mywebstore.co.uk/product/322233]]></link>
            <availability>Delivery 1 to 3 days</availability>
            <manufacturersku>M7652C</manufacturersku>
            <ean>886952780692</ean>
            <price_with_vat>33.00</price_with_vat>
            <size>43</size>
            <quantity>6</quantity>
          </variation>
          <variation>
            <variationid>322233.45</variationid>
            <link><![CDATA[https://www.mywebstore.co.uk/product/322233]]></link>
            <availability>Delivery 1 to 3 days</availability>
            <manufacturersku>M7652C</manufacturersku>
            <ean>886952780692</ean>
            <price_with_vat>30.00</price_with_vat>
            <size>45</size>
            <quantity>4</quantity>
          </variation>
          ...
          ...
          ...
        </variations>
      </product>
      ...
      ...
      ...
   </products>
</mywebstore>

How can i accomplish/achieve the above output?

Do i need the Pro version?

Is there a tutorial in plugin documentation?

Thanx in advance!

The page I need help with: [log in to see the link]