Hydra ^USER^ ^PASS^ not inserting into request uri (http-post-form)

Hi,

Is it possible to pass ^USER^ and ^PASS^ into http-post-form request URI ?
I would like to use hydra in this way:
hydra 192.168.1.1 http-post-form "/authenticate?username=^USER^&password=^PASS^:usern ame=^USER^&password=^PASS^:401 Unauthorized" -l admin -P 'word.txt' -V -t 16

but the result sniffed out in wireshark is:
POST /authenticate?username=^USER^&password=^PASS^ HTTP/1.1\r\n

usernames and passwords are not inserted into request URI . Is there any chance to achieve this without modifying hydra source code?
I can't achieve this with medusa either...

Thank you in advance for any suggestions