Nothing straight forward. There are 2 ways to do that
- custom code
- Data import
Create a advance find query to select the accounts then export them into excel.
Add a another column to your excel file which will the reference field of the custom entity. fill that column with the custom entiy record.
Import the record back into accounts.
I hope this helps.
If you find this post helpful then please "Vote as Helpful" and "Mark As Answer". Amreek Singh Senior CRM Consultant CDC Praxa Sydney, Australia
http://mscrmshop.blogspot.com
http://crm2011usersettings.codeplex.com