Olá, Lucimara,
Tivemos um retorno da SAP, que copio abaixo para te orientar e aos demais que tiverem o mesmo problema.
Thank you for contacting SAP Active Global Support. Please note that now it is possible to create fields up to 30 bytes lenght. You can check SAP Note 1680583. Also, all this info is described on the following link:
http://scn.sap.com/community/abap/blog/2013/11/02/data-dictionary-supports-field-s-name-up-to-30-bytes-length
Let me know if you have any further question or if you still have issues with that.
Aplicamos a nota informada, e conseguimos completar a aplicação da nota 1933985.
At.