ESS --> Working Time --> Time Quotas

How can the cloumn header for the time quotas be changed. for example,one of the columns is labeled as "Entitlement" - we need to change this to " Time Accrued". Can this be done on IMG/BADI/User exit or do we have to make changes on the portal/webdynpro side. what is the best practice if it is possible to achieve the above by both sides (IMG/backend and Portal).

Version: ERP 2005 , ESS 1.0 , Ep 7.0