1st of all thank you for your reply.
Due to customer constraints, we are not allowed to give access to the application.
I tried again running my code snippet and still I couldn't see anything being set in the field. I don't if it make a difference, but the element "select" is disabled (in attach I send you a screen of the page HTML).
One more particularity, is the fact that after this combo, another combo exists to choose the model (based on the choice made in the 1st one).
The way I found to interact with this element, is like so
HtmlControl btnMarcas = ActiveBrowser.Find.ByXPath(
This way I can open the dropdown, type the value (to filter my choices) and then select the 1st one (and only one) in the drop down.
So to summarize, I manage to overcome my issue, but if you could tell me what could be causing my first approach not to work, that would be great.