jQuery Grid Plugin - jqGrid

How can multiple options be set in ajax json for a select type field?

I'm using jQGrid without any problem I mean even about select edit tags and editing(updating database)

BUT

Now I need multiple=multiple for select options, so I used this

[CODE]
{
    "index":"Module[2]"
    ,"header":"products"
    ,"width":"30px"
    ,"type":"select"
    ,"editoptions":{
        "value":"2:show details;4:add item;8:edit or delete item;32:show list;64:add cat;128:edit or delete cat;16:upload;254:all"
        ,"multiple":"multiple"
        ,"size":8
    }
    ,"name":"Module[2]"
    ,"edittype":"select"
    ,"stype":"select"
    ,"formatter":"select"
}
[/CODE]
Note that the values are in persian language (utf8)

And I've made an interface through php to jQGrid options so some of above options are superfluous.

For json result I tested somthing like this : "32,8" or "8,16,128"

Finally however the multiple select have been made successfully for inline(in-list) edit mode and for edit and add pop up but no option have been selected for json response

also I tested "32;8"

I'm on jqGrid 4.4.0

I couldn't find this subject in documentations

I don't know is there any thing wrong with my col model? or I omitted something?

Should I use formatter and unformat to recreate multiple select options or this ability is in jQGrid native?

Thank you Mr.Tomov

jQGrid is perfect