Multi-Select (drop down list) data not saving upon save/email

I have created a drop down list and modified it to allow multiple selection, i.e.

form1.BusinessAreaTable[1].Row1[4].ERP::ready:form - (JavaScript, client)

= "multiSelect";

this.rawValue

= "-1"

However, when I go to save the form and/or email the list fields erase and the data / items I selected are gone.

Please help, thanks.