You have to insert the parameters in the command string being passed over, similar to what you would do with OPNQRYF's QRYSLT parameter. The command string, because it will have blanks, needs to be surrounded by single quotes (&QT in the following example):
[tt]
PGM
DCL VAR(&CMD) TYPE(*CHAR) LEN(2000)
DCL VAR(&LIB) TYPE(*CHAR) LEN(10) value('RMTLIB')
DCL VAR(&FILE) TYPE(*CHAR) LEN(10) VALUE('RMTFILE')
DCL VAR(&QT) TYPE(*CHAR) LEN(1) VALUE('''')
CHGVAR VAR(&CMD) VALUE(&QT *TCAT 'DLTF FILE(' *TCAT +
&LIB *TCAT '/' *TCAT &FILE *TCAT ')' +
*TCAT &QT)
RUNRMTCMD CMD(&CMD) RMTLOCNAME('1.2.3.4' *IP) +
RMTUSER(USER_NAME) RMTPWD(secret)
ENDPGM
[/tt]
"When once you have tasted flight, you will forever walk the Earth with your eyes turned skyward, for here you have been, and there you will always long to return."
--Leonardo da Vinci