Query on EncryptionType and keytype

[KK]

Hi All,
Can anyone tell me if there is any distinction between 
etype [ EncryptionType ]  and keytype as defined in 
section 6.1 and 6.2 of the Kerberos RFC 1510 ?

I specifically want to know whether it will be right according
to the RFC, to service ticket requests from clients for encryption type 
des-cbc-md5 for principals who only have a key of type 
des-cbc-crc in the Kerberos database ?

If I do service this request then I will essentially mapping 
the encryption type des-cbc-crc, des-cbc-md4, des-cbc-md5 
all to a keytype des. If this is the case then shouldn't the RFC be
defining this mapping ?

Any inputs on this are really appreciated.

Thanks in Advance :-)
KK