You sound maybe a bit uncertain about the location of the sensor. Use black tape or some type of lightproof shield to verify the sensor's location, by covering the front face except for a window for the sensor, and test using the CECB's remote to see if it responds.
Regarding the blasting, I have heard of people building a "tent" around the blaster to help concentrate the IR signal by bouncing stray signals back toward the sensor.
Regarding the CECB, make sure the digits you are blasting are correct and produce predictable result. Some CECB's have quirky behavior about interpreting leading zeros or how to account for the 'dot' in the subchannels (does 41 translate to 41.1 or 04.1 or do you have to do 041 to get 4.1 or whatever).