Problem in selecting multiple items in the weblist

[vijay44]

Hi,
I have a weblist, i need to select multiple items in the weblist.
Manually i can do in the application by pressing shift key.

i am using the below code

Code:

Set WshShell = CreateObject("WScript.Shell")
        oPage.WebList("name:=operatingSystems").Click
        WshShell.SendKeys "{SHIFT}"
Browser("browser").page("page").WebList("name:=operatingSystems").Select datatable.Value("OperatingSystems",oSheetName)
    set WshShell = Nothing

The above code does not work. it does not select multiple items.
The datasheet column:operating system has values
windows and imac.

but the above code selects only windows, how to select multiple items.
Any help will be really appreciated.
Regards;
vijay