I've had a look at the source code for setterm and basically it prints some special characters to the terminal.
Using the command-line version of printf it's possible to emulate it.
To set the -blank option do:
printf "\033[9;%ld]" minutes
Replace 'minutes' with a value 0-60.
In my case I used 0 to disable the blanking:
printf "\033[9;%ld]" 0
Just have to wait an see it it works (ok so far).
Thanks for the pointer slacker_et!