salted md5

[sporet]

I would like to crack a hash which is md5(md5($salt).md5($pass)) with hashcat on my ATI Radeon graphics card.
I tried this:

Code:

hashcat-cli64.exe --attack-mode=3 --hash-mode=9 --output-file=out.txt --threads=1 --pw-min=4 --pw-max=12 --custom-charset1=abcdefghijklmnopqrstuvwxyz1234567890 hash.txt

but I didn't get any output, just this:

Code:

Usage: hashcat [options] hashfile [mask|wordfiles|directories]

Try --help for more help.

In hash.txt there is just one salted md5 (hash mode 9 is correct) in the format 32chars:8chars
What am I doing wrong?