Small question about HID USB device

Hi

I'm using USB HID library to implement an small HID device.
I already have read this library and USB 1.1 specification, but I still have a small problem.
I still cannot understand relation between 3 sizes in descriptor:
1- EP0 packet size(that you can specify in usbcfg.h)
2- Endpoint's wMaxPacketSize
3- maximum size of reports

In my case, I need to transfer 128 bytes of data to and from device. Then I have defined my reports like this:
ReportSize(8)
ReportCount(128)
But I still cannot get how wMaxPacketSize and EP0 packet size are related to these values.
From some samples, I saw that people set wMaxPacketSize to 64. But how I should transfer my reports if wMaxPacketsize is 64? or are they related at all?

Regards