How can I remove the default Sitename from a mobile version?

I want to use just the title in the background image of the header as displayed Sitename of the pda-template and dont know in the moment how to get rid of the default displayed Sitename in front. I know that it is possible to remove it, since I already had it just in the way I want it three weeks ago, but I was forced to reinstall the whole component and missed to save the changed templatefiles.
So please give me a hint in which file I can get rid of by default displayed the Sitename.
You will see the problem if you open the site with a "pda" or likewise xhtml-smartphone which reads the mj-pda-template.
best
fahl5

Hi,

Here are some instructions how to change header background with CSS.

Styling Mobile Joomla! with CSS

Does this help?

Try to unpublish mod_mj_header module (this module shows mobile header). Also you can set your logo image in this module settings.

No miothama, that were just the files I searched all the day, because I didn't remebered, that the header has its own module to configure.
Thanks dryabov!
That was exactly what I forgot, that there is a seperate header module, where a logo or sitename can be chosen for the header. Now it is as it should be.
This is real a incredible kind of Joomla- ext.
Congatulation for that.
fahl5