I have to say you may have dug your own grave on that one. I can assure you, your employer will not grant you "permission" to carry while at work. Although many people do it anyways, I would say just do it at your own risk, do not seek any kind of permission from them, if anything, they may use it against you in the future and possibly fire you, its happened before.
Secondly, depends on how easily you can conceal it, your employer is going to look at the risk that clients, other employees, customers, what have you will see it, the possiblility that you go "postal" etc, hes going to weigh all risks involved and probably spoon up some made up BS about anti-gun policies.
Good luck, keep us informed.
Only two defining forces have ever offered to die for you, Jesus Christ and the American Soldier....One died for your soul; the other for your freedom.