Yes, you can use it, but just like at the clear and check you will have to wait for the flashing to stop.
According to SPORTident it may be possible to reconfigure your SI-11 stick to change the duration and frequency of the flashing (or visual feedback cycles).
Here's what they say :
There is exactly one feedback signal cycle from the SI-Station. Then next 11 feedback signals will be transmitted by the SI-Card within 5 seconds. The number and the rhythm of the optical feedback signal can be configured by the user. There is an input mask in “SI-Config”. SI-Card11 feedback signals are powered by battery. Power consumption is very low. Based on calculations there is enough power to activate up to 30,000 flashing cycles.