ProxyErrorOverride On does not work with Apache httpd/mod_proxy_ajp in RHEL 6 and JBoss EWS 1.x/2.x

Issue

• ProxyErrorOverride On does not work if used with mod_proxy_ajp module in Apache httpd in JBoss EWS 1.0.x and 2.0.x.
• When I access a 404 URL in the /app context, which is proxied with AJP, I get a 404 page from backend servers (Tomcat, JBoss EAP, and so on). Accessing 404 URLs via non-proxied content works as intended, as defined in "ErrorDocument". It works in mod_proxy_http (i.e. changing protocol to ajp to http).