Step 1: If you want a shiny then you have to abuse your ID/SID, in this case the Scyther I caught had a PID of 99 (in hex) so enter that in pandoras boxc and go from there.
Step 2: You're gonna need a cute charmer, If you have a high leveled female Jigglypuff somewhere use that, you're probably gonna want to Mimic/Transform/Rage glitch it with sweet scent/spore/false swipe/rage.
Step 3: Hit 1F120227 and enter the BCC, the last elm call I did to get Scyther was on frame 1450 (Kanto response), IIRC SSing in the BCC advances the same for everyone but if not try the adjacent frames.
You should get your Scyther, if not tell me what you did get and i'll try to see what went wrong.