Report module plugin development: hidden report parameter is lost on report configuration

I'm trying to pass report parameter from gadget, and then would like to keep it after going through configuration page, but it's lost.

I expected that hidden report parameter will make it work, but it does not. Is there other way to pass parameter, similarly to selectedProjectId parameter?

Scenario:

    <report ...>
            ...
            <property>
                <key>reportingDay</key>
                <name>reportingDay</name>
                <description>reportingDay</description>
                <type>hidden</type>
            </property>
        </properties>
    </report>

See also Configuring Plugins with Object Configurable Parameters

Url: http://localhost:2990/jira/secure/ConfigureReport!default.jspa?reportKey=jira-timesheet-plugin:projectpivot&reportingDay=2

But after clicking Next on report configuration page value is lost, e.g. http://localhost:2990/jira/secure/ConfigureReport.jspa?reportingDay=&reportKey=jira-timesheet-plugin%3Aprojectpivot&Next=Next