Create regex for log

Hi,

how i can create a good regex to put my logs into piwik ?

My logs are with this format in my website.conf

 LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\"" combined
 CustomLog /var/log/httpd/mywebsite_requests.log combined

I tried the common and common complete log format in the command line but all the visitors are added to the current day…

Thanks for your help,
Regards,

Fred