site logo not shown

a customer of mine is using the pro version of wp touch, and i wanted to add the logo to the mobile version (Ptouch Pro 3.1.7 › Classic Redux). Uploading the png was ok, it is visible in the admin settings, but it doesn’t show up on the mobile website, please help!

here is the website: http://www.sandfarbe.at

https://wordpress.org/plugins/wptouch/