I have a wireless switch with a key fob style remote control. It works fine but the use of a toggle switch has been mandated 
First task is to reverse engineer the remote control. It uses the common EV1527 encoder chip and relies on the data pins’ internal pulldowns to sink current when a button is pressed. This turns on the PNP transistor and powers on the chip.
The device operates off two coin cell batteries and I wanted to keep the device low power. The modified circuit for toggled operation is below:
As shown C101 will charge to +6V. When toggled, Q101 will turn on followed by Q102. C101 will discharge via R102 so after a delay Q101 and Q102 will turn off. Q102 is connected across the push button contacts so this will mimic a short button press. At the same time C102 is being charged ready for the next toggle.
I made up the circuit on some copper clad board and wired it up to the toggle switch
Followed by some Kapton tape and hot glue sandwich to give a compact result:
A 3d printed case completes the job:
