c# - WCF Service + Entity Framework Class Customization -

i'm developing project sql server + entity framework + wcf service.

the main goal map sql server database class objects entity framework, customize them , build wcf service uses objects.

so first part done. i've created database , mapped object entity framework.

for customization part of process, i've done implement new objects inherit entity framework created objects in order provide them custom functionality. far good.

when try send 1 of objects created entity framework wcf service wcf client works ok, when same own object (that inherits ef object) gives me error:

consider marking datacontractattribute attribute, , marking of members want serialized datamemberattribute attribute.

if try include [datacontract] on custom class, says should same base class (created ef). point is: can't change ef classes because lose changes on next update.

can body point me in right direction?

best regards, josé pedro silva