problem uploading to mac app store

i was trying tu upload my game to the mac app store, i used this link to create a .pkg file, i was able to create a .pkg file and uploaded the app(it was uploaded successfully without any errors) to the store but after that i received a mail from the itunes store

"We have discovered one or more issues with your recent binary submission for "Bouncing Cap". Your app has proceeded to review, but the following issues should be corrected in your next submission:

Invalid Signature - the executable BouncingCap.app/Contents/Frameworks/MonoEmbedRuntime/osx/libmono.0.dylib is not signed, the signature is invalid, or it is not signed with an Apple submission certificate. Refer to the Code Signing and Application Sandboxing Guide for more information."

i figured out that the library libmono.0.dylib is not signed so to do that i tried this link but whenever i try to codesign it using the command

codesign -f -s "3rd Party Mac Developer Application: companyname" /path to /Contents/Frameworks/MonoEmbedRuntime/osx/libmono.0.dylib

it gives me an error

3rd Party Mac Developer Installer: company name: no identity found

i have installed the certificates properly following each and every guideline,revoked the certificates reinstalled them, restarted the system but still nothing happens it gives me the same error.even used all the commands provided in this link but still no result same error

can someone please help me out with this .