They shouldn't have to rely on Corporate donations...that is making a 'deal with the devil'.
Simple solution. Form your own non-profit charity and give them big donations from many like-minded others under the conditions that you state, in this case keeping their current policy on gays. (but keep the overhead low)
Talk is cheap.
If they lose all their donors (now) like me who dont want the policy to change , what you think their options would be on this? Only one.
Those who think this important should talk with their $$$.