Hello paolo,

Have you set up your Responsive Template Structure in addition to your Main Template Structure?  The responsive viewports use a separate template with unique headers and footers. 

You need to create a separate header and footer for the mobile/smartphone viewport in accordance with the instructions in the WebSite X5 help file:

http://help.websitex5.com/en/v12/evo/index.html?responsive_ht.htm

http://help.websitex5.com/en/v12/evo/index.html?responsive_template.htm

You customise the responsive template in Step 1 General Settings > Template Style > Responsive Template Structure  -  select 'Header' and 'Footer' in turn from the 'Page Section' drop-down menu.

If you want some text in the header image for the responsive template then you can use a free image editor such as Paint to create one.

You can also choose to display a company/organisation logo in lieu of the text.  Bear in mind that at mobile resolution the header can become very cramped, so the simpler the better.

Kind regards,

Paul