"No information available in this stupid shop!"

Don't be so rude about the shop - you bought the things!!!

The detector might not be a simple transistor - it might be a receiver chip with Vcc, GND and Data connections.

The polarity of a transistor can be determined from a simple diode test, remembering that a transistor "looks like" two back-to-back diodes: common-cathode for PNP; common anode for NPN. This also identifies the base.
Then connect it in a suitable common-emitter configuration, guessing the collector, and measure hfe; reverse your c-e guess and measure again. The best hfe reading is with the transistor the right way around!