Civicrm 1.7beta installation on 1.012 - Joomla! Forum

how civicrm 1.7 beta installed , working 1.012 ? see working on demos , such have had no success on 3 seperate attempts install. have civicrm working on joomla 1.5 test site know i'm capable of reasonable install the civicrm 1.7 , joomla 1.012 has me stumped now. help, please !!!