Why not simply put the style sheet in http://yoursite/themename/modules/yourmodule/ ?

i dont want to put the stylesheet in the module template overiding folder cause its a completely different theme.

In order for the stylesheet to work both themes should have same structure, shouldnt they? Am I missing something?

The code that i quoted actually works it changes the session variable. I can see it works, because if i log out, the logout screen is the one from the theme that i want to actually load.

so i need something the will make it happen after the core has loaded the selected xoops theme.

is this information also stored in a cookie or something?

wouldn't this work
Themes : Create Your Own Multi-Themed Xoops Site
with creating a new smarty variable that hold the theme from the choice that will be the argument

just a though

doesnt work cause the theme variables xoImgUrl, theme name etc of the two themes look in the xoTheme object which gives the folder name of the pseudo theme set in the xoops preferences.

I also tried deface which does what i actually want to BUT

it will only show the theme set in the defacer module no matter if a user selects the second one or not :/ :(