I know it'a a long time since your post, but I just read it...
In fact you can edit conf files in Askozia:
There are a couple of hidden pages in addition to those in the webGUI to aid in troubleshooting problems:
/exec.php - execute shell commands, download / upload files
/status.php - show system status (df, ps, etc.), xml config, raw logs, sip/iax registrations/peers, generated .conf files
/diag_editor.php - file editor
/debug_isdn.php - captures ISDN debug output
This is on the Askozia web site.