Trying to stimulate the immune system into producing antibodies to the active form of angiotensin, an enzyme involved in the complex balance of chemicals that regulate blood pressure, might not be the safest point of intervention for this disease. Considering the prevalence of autoimmune conditions, I would be concerned about the possibility of long-term effects. Nevertheless, according to the New Scientist, Cytos Biotechnology in Zurich seems to be trying out such a "vaccine".
Perhaps we should start training the immune system to attack a variety of other targets as well! Neurotransmitters for "mood disorders"? Hormones? I'm sure the resulting inflammation would be negligible.