STRPASTHR question

Here's a screen-shot from a customer's DSPNETA:

                           Display Network Attributes
                                                             System:
S123456
 Current system name  . . . . . . . . . . . . . . :   S123456
   Pending system name  . . . . . . . . . . . . . :
 Local network ID . . . . . . . . . . . . . . . . :   APPN
 Local control point name . . . . . . . . . . . . :   S123456
 Default local location . . . . . . . . . . . . . :   S123456
 Default mode . . . . . . . . . . . . . . . . . . :   BLANK
 APPN node type . . . . . . . . . . . . . . . . . :   *NETNODE
 Data compression . . . . . . . . . . . . . . . . :   *NONE
 Intermediate data compression  . . . . . . . . . :   *NONE
 Maximum number of intermediate sessions  . . . . :   200
 Route addition resistance  . . . . . . . . . . . :   128
 Server network ID/control point name . . . . . . :   *LCLNETID   *ANY


I've set up the line, controller, and device descriptions to allow
pass-thru using the command STRPASTHR S123456.  I'd like to be use
STRPASTHR CUSTNAME instead.  How do I change my configuration to allow me
to do that?