Yes, the key is extremely easy to extract if you have capsrv's code....they were smart enough not store the key itself, instead the ipad/opad (Key ^ 0x363636...., Key ^ 0x5C5C...) are loaded via MOVK instructions.
Still, not hard if you know what you're doing.
On 2.0 the Hmac function is at 0x7B94 in .text, it takes in (pointer to output mac, pointer to jpeg data, size of jpeg data, pointer to output size_parsed variable)
I guess I can tweet a pic this evening when I'm doing switch stuff, heh -- didn't bother since it's only screenshots...