Custom GL on InterCompany transactions

Hello,

I have a need to create IC code also to balance sheet.
I imagine to do this with custom GL but i'm facing some errors.

Has anyone done script like this?

My code :

function customizeGlImpact(transactionRecord, standardLines, customLines, book){

              var newLine = customLines.addNewLine();
              newLine.setCreditAmount(transactionRecord.getFieldValue('total'));
              newLine.setAccountId(standardLines.getLine(0).getAccountId());
              newLine.setMemo("CustomGL");
              newLine.setBookSpecific(true);
              newLine.setEntityId(standardLines.getLine(0).getEntityId());

              var newLine = customLines.addNewLine();
              newLine.setDebitAmount(transactionRecord.getFieldValue('total'));
              newLine.setAccountId(standardLines.getLine(0).getAccountId());
              newLine.setSegmentValueId('cseg_gs_ic_code', 3); //This is the wanted value in the custom segment.
              newLine.setBookSpecific(true);
              newLine.setEntityId(standardLines.getLine(0).getEntityId());