http://localhost:2525/crmreports/viewer/viewer.aspx?id=<reportid>&helpID=<report RDL name> &action=filter

You can write a jscript function to manage online and offline:

<Button Icon="/_imgs/btn_off_lookup.gif"

      JavaScript="

      if (!IsOnline()){

        crmForm.RunReport(false, '\x7b4CE79392-A05F-E011-AF5F-005056862C11\x7d', '', 1, 'SalesReport.rdl');

      }

      else {

          url = 'http://localhost/ReportServer/Pages/ReportViewer.aspx?%2f<orgname folder>%2f4.0%2f%7b4ce79392-a05f-e011-af5f-005056862c11%7d&amp;rs:Command=Render&amp;SalesReportId=' + crmForm.ObjectId;

          window.open(url);                                 

       }"

       PassParams="1" WinMode="0">

<Titles>

  <Title LCID="1033" Text="Print Sales Order" />

  <Title LCID="1040" Text="Stampa" />

</Titles>

<ToolTips>

  <ToolTip LCID="1033" Text="Print Sales Order" />

  <ToolTip LCID="1040" Text="Stampa" />

</ToolTips>

</Button>