Lawyer´s Agreement, Petitions Fees

[tambirita]

Hello everyone:

I have a corporation interested in sponsoring my PERM Labor Certification + I-140 Immigrant Petition for alien Worker, but the lawyers want me to sign an agreement with them by which I am in charge of everything and pay everything, including the recruitment. Is it legal or it is my sponsor who should do it?.

Can anybody help with it?. Thanks in advance.