HOA Nut House

I live in a subdivision with an HOA. Recently we submitted plans for the addition of a storage unit. We were "denied" on the basis that it was not within the parameters of the CC&R's. Interestingly enough, the CC&R's do not contain guidlines regarding structures, and merely state that proper screening is required. Please note, that our plans included mature trees to mask the visibility of the unit. We then requested a hearing with the Board at which time we provided them with numerous homes in the subdivision with existing storage units. We were also told that the Architectural Committee had guidelines that would be provided to us. After months of requests, we are now told that there aren't any. Apparenlty approvals are based on opion. I failed to mention that my neighbors all signed a affidavit stating that they were ok with our addition. Where does a homeowner go from here? The Management Company and Board are basically brushing us off and we can't get answers. Help!