Sharepoint 2010: Update Lookup Field Multiple Value with a Workflow

I want to update a lookup field that contains multiple values through a Workflow, using Sharepoint Designer 2010.

F开发者_运维知识库or the moment, the old value is always overwritten, and I would like to "merge" the old value with the new one.

Here is the list of my test by so far:

1) I've managed to Keep the old or the new one, but not both of them. 2) I've tried to add key words like : & ; , between the fields, but only the first element is written in the list ( Example : [%first Element: id%] ;[% Second Element: ID%] --> Result in the column : First Element Id)

I'm out of idea. Do you have any tips?

Do you need more information?

Is this possible to do such things in Sharepoint designer?

Yes this can be done in SharePoint Designer. You need to set both the ID and the lookup value (the text that is displayed in the lookup field) - and these need to be separated by ;#

Build the following as a string before setting it to the lookup value.

[%Current Item:LookupList%];#[%Variable:NewItemID%];#[%Variable:NewItemTitle%]

In the example above, the first item is your original multi-select lookup list. The second, is the ID from the item that you want to add to the lookup, and the third is the title (or the value you're displaying in the field) from the item you're adding.