I want download a file via httpengine, but the file is too big for WAP gateway, it's about 1000k

so I have to divide the file to a few part and just down one part everytime. First time down from 1 byte to (500*1024 )byte, and second time from (500*1024+1) byte to (1000*1024) byte

it seems to use HTTP::ERange could do this, but how, can anybody give me a example?