For all those that are trying to have different menus in each language they are using here is the patch .... that works for me
in the example i will use 2 Languages English and German
first we take a copy of params.ini (templates/rt_maelstrom_j15 in my case)
we rename it params-en-gb.ini (we edit the file and we change the line that says
menu-type-fusionmenu-menutype=mainmenu >>> we put in mainmenu the menu we want for english (mainmenu)
we copy again the params.ini to params-de-de.ini and we change the line
menu-type-fusionmenu-menutype=mainmenu >>> to the menu we want for the german (mainmenude)
now we have 3 params.ini files in templates/rt_maelstrom_j15
we leave the original params.ini file because the changes we will do in the template from the administrator menu will change this file (RT super developers will solve this issue till 2013)
now we go to
/components/com_gantry/core/gantrytemplatedetails.class.php