STR \ Coun max len?

Hi,
Is there way to make count for STR to be larger than 1 byte. As far as I can see in pbppic18.lib it uses only one byte for countdown. I can make 2 byte counter, but I can't find where is stored high byte of count.
I need to receive 700 bytes in array...
I'll try to solve it with FOR/NEXT...