Well i changed a second time the navigationlink by changing the target in ZSLA to 'Account main view' by creating component usage of BP_HEAD , and then the 'CX_BSP_WD_INCORRECT_IMPLEMENT ' doens't appear any more but the the account is showing up but there is no BP data in this page .
Wich is logical because the 'for PACK Details' locates in component BT116H_SRVO and the component ZSLA is just a custom component that was created by another person in order to show a report of service orders , and when the user clic on an id of an order he got the mainWindow of BT1116H_SRVO .
So i think the problem is because the mainWindow of component BT116H_SRVO is called in the custom component ZSLA , and as the component BT116H_SRVO has an outboundplug 'BP' , this outbound plug is also detected in component ZSLA even if the button concerned is in BT116H_SRVO .
To summarize : the source is ZSLA , the target is BT116H_SRVO and through MAINWIENW of BT116H-SRVO and op 'BP' we got the BP view .
So in my opinion there is no need to add a navigationlink in custom component ZSLA .
Thank you again for you help and sorry if i disturbed you 