problems with contextual filter backtracking node references Drupal 7.19

I have two content types defined:  Package and Account.
In the Package type, a Node Reference field is provided as field_account.

I have two packages that each have a reference to one account.

In the Package display, a link is given for the Account.  Clicking on that link shows the Account.
--now my problem--
On that Account page, I wish to add a block that provides links back to the two Packages.

I have been trying and trying to use Contextual Filter and just can't get it...
Appreciate all the help,
--Scott
Under the contextual filter, check 'Provide default value' under 'When the filter value is NOT available' and select 'Content ID from URL' as the type. Your view should work.

Conceptually, you wish to list 'Packages' in the Context of the Account you are displaying.