proxy_ajp webdav http 1.1 authentication

["Michele Mase'" <michele.mase@xxxxxxxxx>]

I've the following problem:

A ftontend server with apache2.2.x (http1.1)
mod_proxy
mod_proxy_ajp

A backend server:
tomcat 6.x with 2 webapps:
/app1
/app2 (webdav, basic authentication via http)

Problem:

/app1 works well under proxy_ajp:
ProxyPass /some_path ajp://server:8009/app1

webdav authentication cannot work under proxy_ajp
It works only under proxy_http:
ProxyPass /path http://server/app2
ProxyPassReverse /path http://server/app2

Are there some limitations in proxy_ajp module?
Could webdav authentication work with proxy_ajp?
Michele