How to use Log Analytics Tool to push custom log records into piwik?

I’m a newbie to piwik, so please excuse my ignorance.

I have an existing application which generates access log records to track POST events to a website. Here’s a sample log record:
10.18.10.198 - myjournal [26/Jul/2013:11:29:08 -0700] “POST /10.18.10.201/nvevents?user=sam&event=clicked item 123 HTTP/1.1” 200 0

The application can be off-line which is why log records are use until the application comes back on-line. I created a website for nvevents on my piwik server and ran the import_logs.py tool using the following command:
python import_logs.py --idsite=2 --url=http://10.18.10.201/piwik access.log

The visitor log shows a site request but I thought I’d see (user,event values) as custom variables? Or am I’m totally mis-understanding how this works? I would like to have my application’s log records pushed into piwki for analysis. How many times a user clicked on an item?

Should I create a custom plugin to support my application’s data?
Any help or guidance would be appreciated.
thanks

The URL parameters will appear in the Actions>Pages report, which lists the page URLs. the importer will not automtaically set the parameters as custom variables.

Thanks for your response.

When I run the import, I see the URL parameters under Action->Pages report.

I noticed that when I changed the log record as:

192.168.1.71 - nvcore [28/Jul/2013:08:58:32 -0700] “GET /nvevents?action=nvevent&event=2013-07-28T08:58:32 played a program HTTP/1.1” 200 0 "

I do not see Actions->Page information but under Actions->Site Searches I see the data I specified as event= . For example,
event=2013-07-28T08:53:57 played a program appears as site search keywords.

Is there a way to change my log record to show both Action->Pages and Actions->Site Searches with the keywords?
thanks