var my_pstyle = app.selection[0].paragraphs[0].appliedParagraphStyle; 
my_pstyle.nestedStyles[0].properties = {appliedCharacterStyle:app.activeDocument.characterStyles.item("my_charstyle"), inclusive: false, repetition: 1, delimiter: "^t"}; 
my_pstyle.nestedStyles[0].properties = {appliedCharacterStyle:app.activeDocument.characterStyles.item("[ohne]"), inclusive: true, repetition: 1, delimiter: "^t"}; 

var my_sel= app.selection[0]; 
my_sel.nestedStyles[0].properties = {appliedCharacterStyle:app.activeDocument.characterStyles.item("my_charstyle"), inclusive: false, repetition: 1, delimiter: "^t"}; 
my_sel.nestedStyles[1].properties = {appliedCharacterStyle:app.activeDocument.characterStyles.item("[Ohne]"), inclusive: true, repetition: 1, delimiter: "^t"};