SignalTap II does not capture full sample buffer

Hello,

Whenever I set up SignalTap to have a particular memory buffer (2K, 4K, 8K, or 16K), I am never able to actually capture the entire memory buffer. It seems like I should be able to do this - for instance, Xilinx ChipScope Pro supports this, and the memory is available in the FPGA for a full capture. If I select a 16K memory buffer, I get output sample indices -2 to 14336 rather than 0 to 16384 as I'd expect (or some offset from that due to trigger position).

Is there a way to get the full memory buffer?

Thanks,

Nathan