How to set video scaling in Mplayer's config file

Hi. Trying to reproduce my video scaling command in Mplayer's config file, I receive this error message:

Quote:

Option vf needs a parameter at line 2

What I placed at config it is:
Quote:

vf scale=1024:-2

, which is the same I use at command line, except by removing the '-' character.

So, I only need to know what small change I have to do in this line. Thanks for the attention.