Do you work at a store in the mall? If so maybe you could lock your bike up inside the store you work at, maybe in an employees only area? If your employer refuses to give you free accommodations, I don't think that should force the mall management to give you free accommodations. Have you thought about offering to pay for (or help contribute towards) the type of parking facility you feel should be installed? If it's not going to increase the number of consumers spending money in the mall, store owners/mall management probably won't consider it worth spending any money on.