Convert string to VCO AD object type (computer name)

Hi,

I would like to convert the name of a computer (entered as a string) to an AD computer object to add to a security group. I was trying to accomlish this by using a built-iin workflow "Add computers to group members". After changing the workflow as follows:

input: requestedName

attribute: SecurityGroup

scripting:

userGroup.addElements(requestedName)

error message: Cannot convert baltacagnt01v to ch.dunes.ad.object.interfaces.IADBase[]

How do I convert a string to an AD object name? Should I consider using something besides this workflow?