Look at their website:
Employers must receive approval from the SINP to participate in this category before you start working for them. The SINP won’t accept your application if you start working for the employer before this approval is received.
http://www.saskatchewan.ca/residents/moving-to-saskatchewan/immigrating-to-saskatchewan/saskatchewan-immigrant-nominee-program/applicants-with-saskatchewan-experience/hospitality-pilot-project
Did your employer offer you the job with SINP in mind? I am not sure the cert of registration means but judging from the checklist[1], the cert of registration is just a support document, and your employer needs to apply for Job Approval Letter, then you go and apply for SINP.
I got my Job Approval letter with my employer through a representative so I don't exactly know how they've done it. But does explicitly say "Job Approval Letter" on it so maybe it's not what you have on hand.
