this salt string doesn't conform to the format of the other crypt type, so it forces the standard encryption type.
if you want to use on of the other crypt encryption tupes, you must make sure the salt string conforms to what is expected.
for example, to use the extended encryption type:
CRYPT_EXT_DES - Extended DES-based hash. The "salt" is a 9-character string consisting of an underscore followed by 4 bytes of iteration count and 4 bytes of salt. These are encoded as printable characters, 6 bits per character, least significant character first. The values 0 to 63 are encoded as "./0-9A-Za-z". Using invalid characters in the salt will cause crypt() to fail. 
the example code uses this for the salt:
'_J9..rasm'
your server _does_ support them all, but your salt string does not conform to the format that needs to be used for any of them.
