How to generate uuid for a soap script that is constant

I added at the project level and using it like this at two consecutive calls.  Both places i see different uuids being used.

I added under project settings / properties like this. - ${=java.util.UUID.randomUUID()}

${#Project#uuidar}
"dae35c8e-97df-49a5-9fc3-d0bcad1db922"
"90a050ea-173e-4e59-aa6b-de9e91d91dcb"