Multi Store Shipping Weight Measures problems

I have a multi store setup with 3 stores. One store sells items to the USA, Once store sells items to Canada and one store sells items to Europe. Each store is configured with their own payment processor so the monies go to the correct bank accounts for each store.  
Each store also has the shipping configured for the appropriate postal service for their region. USA is configured to use USPS, Canada is configured to use Canada Post, Europe is configured to use Royal Mail.

I have the nopcommerce weights set to Ounces. (There is no way to set different weights per-store)
The problem is when it comes time to calculate shipping ... USPS returns postage just fine based on Ounces for our USA customers. The Canada Post shipping method (api) is designed to return weights based on Kilograms so it returns postage cost at a rate far greater than it should for our Canadian customers. 1 Ounce = 0.0283495 Kilograms.
So if I have an item that weighs 1 Ounce it returns a postage cost of 1 Kilogram instead of 0.028 Kilograms. That is a big difference.

Unless there is a configuration I am missing, this seems like a HUGE oversight in Nopcommerce.
Does anyone have any ideas how to fix this? Without the correct weight measurements being sent to the shipping providers multi store is not useable.

You don't mention what specific plugin/plugins you're using but assuming it's the default USPS and Canada Post plugins that are included when you download nop then they look like they both contain code for converting to the correct weight unit before doing any calculations (see links above). Are you sure you've got the weights and measure ratios configured correctly to do the conversions?

Not sure about Royal Mail as I'm not aware of any plugins for it but going by the code in the others then it seems reasonable to assume that it's the responsibility of the plugin to perform the conversions to the units it requires (which makes sense as even a single store could use multiple shipping calculation providers that require their own base units).