Can not match property fields with attributes

Hi there!

I´m trying to import a custom XML from a provider and having issues with the languages. 

I have descriptions in the format shown below. Short and Long descriptions have a lang attribute (and the lang order can change from property to property). So using a {/descriptions/short_description[n]} works in parsing the fields but is not an option for us. 

We tried with other Xpath selectors as
long_description[@lang=’es’]
long_description[@lang=”es”]
long_description[contains(@lang, ‘es’)]

And doesn’t work.

Any idea? Are we doing something wrong?

Thanks, and I hope you can help as fast as possible.