Hi Roberto,
Thanks for your reply.
I have run the OSoftSSIS2008_Client installation to register the BPC 10 custom tasks and also copied the new dll in SSIS task folder, now as we are not changing the SQL version so should registering the tasks will do or first I need to run the migration via Server manager so that packages created in 7.5 with old dll names should work in BPC 10.0
Thanks & Regards,
Rohit