An A319 Captain reports operating against the advice of Maintenance Control and continuing to destination when dealing with an ECAM for low center fuel tank pressure

Narrative

Shortly after established in cruise; an ECAM message came on; and stayed on; for FUEL CTR TK PUMP (1) LO PR. (This often happens; but normally clears itself within a few seconds.) After a minute or two of waiting for the ECAM to clear; we complied with the steps of the ECAM (X Feed On; and Ctr Tk Pump (1) Off.) The ECAM cleared. The First Officer soon noticed that the fuel load became unbalanced and was getting worse due to both engines feeding out of only the right wing inner tank. The center tank was empty and each outer wing tank had a little over 1500 LBS. At about 1500 LBS out of balance and increasing; I decided to turn off the X-Feed. This stopped the out of balance from getting worse. We then contacted Maintenance Control and discussed the situation. They advised us that the flight manual required that the X-Feed remain open. I advised him that that would put us into a low fuel divert situation unnecessarily; and that if we just left the X-Feed closed that we could continue tank to engine normally. He advised that I could do that only using Captain's emergency authority. After discussing the situation with the First Officer; I decided to leave the X-Feed closed to avoid a diversion and avoid creating an out of limits imbalance. We continued without incident and always within limitations of fuel balance. We landed with over 10;000 LBS of fuel; and an 1800 LBS imbalance (the right engine burned 300 more than the left.)