Hook into project_issue_view to inject cck field info

From issue.inc in the function project_issue_view():

    // Allow modules to alter the metadata displayed in the table on the actual
    // issue node itself (at the very top of the issue). Modules should accept
    // the $current_data parameter by reference and add additional
    // elements for additional lines in the table.
    //
    // Modules implementing this hook should take the following parameters:
    // @param $view
    //  A string representing the metadata view being generated.  For the issue
    //  node main table, this will be 'current'.
    // @param $node
    //  The project_issue node object.
    // @param $current_data
    //  An associative array of rows in the project issue metadata table that
    //  will be displayed, with the following key/value pairs:
    //    'label' => The metadata label.
    //    'current' => The current metadata value.
    //  This parameter should be accepted by reference.
    foreach (module_implements('project_issue_metadata') as $module) {
      $function = $module .'_project_issue_metadata';
      $function('current', $node, $current_data);
    }

So, just implement this hook. For example,

function my_module_name_project_issue_metadata($view, $node, &$current_data) {
  if ($view != 'current') {
    return;
  }

  $current_data['my_new_property'] = array(
    'label' => 'My label',
    'value' => 'my value',
  );
}