Note that there are two ways to set a variable of the type BITS like e.g.:
SYNTAX BITS {telnet(0), ftp(1), http(2), icmp(3), snmp(4), ssh(5), https(6)}
1. Using type "b" and a list of bit numbers like:
snmpset('FOO-MIB::bar.42', 'b', '0 1 2 3 4');
with the disadvantage that the success is not easily verifyable as an snmpget() for the same OID would return e.g. 0xF8.
2. Using type "x" and a hex number but without(!) the usual "0x" prefix:
snmpset('FOO-MIB::bar.42', 'x', 'F0');