I'm struggling to understand why you cant use both .FSP and .HSP files. As I understand it, you have to use one or the other. But a quick google comes up with this.

\ Content \ histspeed
* .HSP – Files that CONTAIN historical information about traffic on certain routes in certain period

\ Content \ map
* .FSP – File that contains information about legal maximum speed of travel.

Please explain like i'm 5!!