Yep.
At the time of this posting, Alexa Routines cannot be triggered from most Switches, and that includes the ones connected to smartthings.
It can be triggered from a Contact Sensor, a motion sensor, or a lock. Physical or virtual.
So the trick is to have a virtual device of a kind that Alexa will use to trigger a routine and then have your virtual switch change the state of the virtual sensor/lock.
Your options will be somewhat different, depending on whether you have a Smartthings/Aeotec hub, but the basic idea is the same.
See the community FAQ: