TSOP IR receivers will filter out as noise any modulated signal that is continous for more than a few miliseconds. So all you need to do is connect a microcontroller to the R pin on the 555 IC. This pin should be connected to Vcc through a 100k resistor, not directly. Basically you toggle the output pin from the microcontroller from Low to High and back to Low, for a few miliseconds. Instead of the microcontroller you could use a second 555 tuned for a low frequency that will turn on and off the first one.
If you use Panasonic PNA4602 (38kHz) you don't have this problem.