Define a Header/Total for Liabilities and Net Assets. Here is how it should look on the VCO:

Header/Total Liabilities & Net Assets at level 1
Header/Total Liabilities at a level 2
Account Detail for Liabilities
Header/Total Net Assets at a level 2
Account Detail for Net Assets

Once the VCO is saved and the Balance Sheet rerun, there will be a line that is the total of the Net Assets and Liabilities.

NOTE: The fix above is only valid if you have not already set up your Account Details for Liabilities and Fund Balance.
If you already have the Details configured, do the following:
 

  1. Insert a New Header/Total and move to above Liabilities.
  2. Move Liabilities & Fund Balance down to the level below your new header/ total.
  3. This will total your Liabilities and Fund Balance.