EB-2 : Where to get experience letters from if I have no prior employer?

My current employer is filing my PERM application and wants me to get experience letters. Since this is my first job out of school and I have no prior employers, is it acceptable to get these from my current supervisors?

Acc to my lawyers, the Department of Labor typically don't accept letters from the sponsoring organization. I'm not sure how to proceed with this, any help?