Customizing the metamodel : Diagrams: Creating and modifying : Adding numbering to hierarchical diagrams
  
Adding numbering to hierarchical diagrams
You can specify that nodes in a hierarchical diagram (such as an Organizational Chart, a Process Decomposition diagram, a Functional Hierarchy diagram, and so on) be numbered through USRPROPS.TXT.
To turn on numbering, declare these two properties for the diagram type:
DIAGRAM "hierarchical-diagram-type-name"
{...
PROPERTY "Hierarchical Numbering" { EDIT Boolean LENGTH 1 }
PROPERTY "First Node Number" { EDIT Text Length 20 }
...}
When “Hierarchical Numbering” is set True for a hierarchical diagram, System Architect numbers the nodes as follows:
Every child node is given a number equal to its parent’s number with a period and the ordinal number it has among its siblings appended. For example, the third child of a node numbered xyz acquires the number xyz.3.
If is numbered 0, the children are numbered 1, 2, 3, and so on.
If no value is given for the “First Node Number”, the “root” (or “top-level”) nodes are numbered 0,1, 2, 3, and so on. (Remember that a hierarchical diagram can have many hierarchies in it.)
If the “First Node Number” has a value of 0, this is deemed a special case and the root nodes are numbered 0, 1, 2, and so on. It is seen that, if there is more than one root node, there will be duplicate numbers.
If the “First Node Number” has any other value, that value is inspected to see whether its trailing characters are numeric. If they are, they are treated as the first root number, but with the preceding characters preserved throughout. Thus if the “First Node Number” has a value of xxx4.7, the root nodes are numbered xxx4.7, xxx4.8, xxx4.9, and so on. If the rightmost character of the “First Node Number” is not numeric, the numbering used is as though it had a trailing 0.