Change Currencies disabled, for imported CRM accounts?

Change Currencies disabled, for imported CRM accounts?

Hi,

I have accounts that i have imported from CRM, now i want to change the currency to USD or AUS.
However, I can not seem to be able to do this! can you please advise as this is a big problem!

The issue, I can not specify the Currency in the CRM, as such I have no way of telling invoice that this client should be using USD $ or AUS $ etc....

Abs