Bizagi code (my version)
The below code helps you trace the location of any uploaded document in Bizagi:
var uploadPath = CHelper.getParameterValue("uploadPath");
var IdEntity = CEntityManager.GetEntity("entity-name").Id;
var IdAttribute = CEntityManager.GetEntity("entity-name").Attributes["attribute-document-name"].Id;
var SurrogateKey = <entity-name.Id>;
var WholePart = (SurrogateKey - (SurrogateKey % 1000)) / 1000;
var bizagiFilePath = uploadPath + "\\" + IdEntity+"\\"+ WholePart +"\\"+ SurrogateKey +"\\"+ IdAttribute;