Currency Issue

[Les]

I have a bank with multiple currencies.  The primary currency for this
bank is HKD.  Within this account I have a folder "saving" and type is
cash.  Under "saving" is a folder "currency" with type cash and contains
several other folders: CNY, HKD, etc

Everything works fine except CNY does not roll up properly (it does not
maintain an exchange rate for CNY:HKD).  Is there a way to solve this? 
Using LMDE v 1403 and GC 2.4.13.

Thanks,
Les