INTERFACE MMC/SD WITH USB CORE

I made changes as in infocenter.arm.com/.../index.jsp to use mmc/sd within usb core:

void MSC_MemoryRead (void)
{
    U32 n;
   ...
    mmc_read_sect(Offset,Memory,n);// Call your function to read from the flash card.
    USB_WriteEP(MSC_EP_IN, &Memory, n);   // Send the data through the endpoint.
    ...
}

but this not work,I check mmc_read_sect and return TRUE, I am using LPC2468 mdk and rl-arm 3.40. When I use usbmem example the drive appears in explorer and I see "readme.txt". But when I change to mmc/sd not happens. Anybody already use this or have some tip? thank you!