How to map ID of CaseID from a sucessfull form submit?

Hi, i'm using bonitasoft 7.1.5 and i'm trying to map the Caseid from a successful form Submit to get the id of the next task in the list. In theory it works, when i press submit in the form i can see the caseID that i get from the request, but the variables from wich i get the id remain empty, any idea why?
* got 2 variables.
- Caseid = null
- InfoCaseID = http://localhost:8080/bonita/API/bpm/humanTask?c=1&p=0&f=caseId={{Caseid.caseId}} (empty)

Problem with locale accessing bonita forms by url


I am trying to access to bonita using this url: http://localhost:8080/bonita/loginservice?username=xxx&password=xxx&redi...$entry&process=ID_MY_PROCESS&mode=form&locale=fr