This has some bearing upon a similarly tilted forum thread by ustulation.
The ThumbnailBuffer member of both the CITP_MSEX_1.1_ELTh structure and the CITP_MSEX_1.1_EThn structure is listed as:
uint8 ThumbnailBuffer;
This should be
uint8 ThumbnailBuffer[];
or
uint8* ThumbnailBuffer;
Otherwise, the structure would only return the first byte of the buffer.
tom