Symfony 2 doctrine onUpdate cascade

I am using Symfony2, Doctrine 1.2 and Doctrine/ORM 2.2 for one of my projects. I am trying to make one of my entities to cascade one of its foreign keys "onUpdate". This is pretty clearly not supported by doctrine ORM annotations. However, I really need to have the ability to auto-update this foreign key in both tables.

Is there any way to do this?

Thanks in advance for any help!!

Cheers!