Auto-populating Storm Invoice
I'm not sure but maybe the Computed Field can be used, you can even use it to fill another field.

If you are ready for some custom code (although Computed Field will probably require some code too), you can implement hook_nodeapi() when $op == 'prepare'(or hook_prepare() in Drupal 7). There you can pre-fill new Invoice node (when $node-&gt;nid is not set, the node is being created).