Associated View Doesn't show data for 1:N Relationship with Account Entity

I am new to CRM 2011 and pretty new to the forum as well so would appreciate all the assistance I can get.

I have a very simple scenario. I have a custom Entity called let's say X. This Entity has a relationship with the Account Entity (1:N) i.e. One Account can have Many Xs. The common field between Account Entity and X entity is The Account Number. 

I added a 1:N Relationship on the Account Entity. The issue that I am seeing is that when I select and Account and click on X under the Related Menu on the left Navigation it doesn't show me related Records from X.

Am I missing anything? any assistance would be appreciated.

Thanks
Zubair