How To Shorten the Length of a String Parameter

Hi, Everybody!...

I wish to load test a SOAP web service. One of the parameters needs to be unique for each invocation. I am presently using ${=java.util.UUID.randomUUID()}. Lamentably, I am getting the following error: String '<some UUID string>' is too long (length: 36, maximum allowed: 35).

How can I shorten the length of the parameter?