How Asset clearing account will get knocked off for Foreign Invoice

Business scenario:

Asset AP invoice created in CAD Operating Unit in USD amount 1000$ (800 CAD).
When Transfer to GL is Ran Asset clearing account Dr and AP Liability Cr for both entered and convered amount will go to GL. SO both USD and CAD will go to GL
When Mass addition is ran in FA CAD books 800 CAD will get capitalized.Asset Dr and Asset clearing Cr 800 CAD..With this asset clearing account will nillify the CAD portion(800 CAD)

Now questions is how 1000$ USD will get cleared off. 

Quick response is highly appreciated.

Thanks,

Nags