retrieving time in milliseconds? (using v. 9.1.2)

I am trying to retrieve the current time, down to the number of milliseconds. I can't find any way to do this (I am using v9.1.2). If I use "clock milliseconds" I get the error

 

 

01070151:3: Rule [timestamp_remove_add2] error:

 

line 3: [invalid option "milliseconds" must be: clicks format scan seconds] [milliseconds]

 

line 5: [command is not valid in the current scope] [}]

 

 

"clock seconds" works fine. I can use "clock clicks -milliseconds", but that doesn't give me the actual time - just the click count expressed in milliseconds, which doesn't seem to be tied to any meaningful zero point. Is there any way to get the current actual time down to the millisecond level?