Connect h323 phone with a Sip Phone

Hello

I´m Running Asterisk with h323, i can register a SIP and a H323 Phone, When I trie to connect two sip phones works well, when is two H323 phones work well, but when i trie to connect a sip phone with a h323 phones don´t work ??
Any Suggestion

yes, post logfile chunks relevant to the call, and more information/detail about what “doesn’t work” means.