Import work on administrative project - by: bioN

Hello,
I've got a project with the administrative type (so anybody can enter work on it). This project has two activities and now i want to import work on these activities. The problem is that when importing work we need the id of the assignement (idAssignment) which is not created on administrative project because everyone can access it. How can i do it ? Do i have to assign every resources to these activites?

thanks.