Have this person present your case. Present a clear rationale for the proclamation. Officials want to know that they are not alone in taking this step, that people will appreciate it, and that the organization being honored will not embarrass them. Reassure them on all counts. Recognize the proclamation publicly.
Officials like to be thanked.
In front of others. Keep up your contacts. Put whomever helped you get that proclamation on your mailing list and update them regularly on your work. Save the proclamation and use it to convince them on future occasions to do it again. Proclamations are cheap, painless, and easy, but can have enormous value in affirming your work and cause.