LDAP attributes and schema changes

hi,
i have to create the following attributes to be used for my ldap directory. i can match the existing attributes with some of the fields. I want to know whether for rest of the fields if some attribute exists or i have to modify the schema.

database fields-------->attribute

First_Name --------------> cn (can be used)
Second_Name -----------> sn
Title ------------------> personalTitle
Designation ------------> title
Organization -----------> o
Employee Id------------> uid
Location --------------> l
Work_Number----------> telephonenumber
WORK_FAX------------> facsimileTelephoneNumber
Mobile_Number--------> mobile
Home_Number ---------> homePhone
Email_Work------------> mail
Address------------>postalAddress

the remaining database fields are:

WORK_PAGER
Email_Home
deskno
PHOTO_URL
ManagerNo
NICK_NAME
MIDDLE_NAME
ANNIVERSARY
BIRTH_DATE
WEBSITE

does any attribute exist for these above given fields? If no, do i have to alter the schema?
is it good practice to create your own object class or alter the existing object class?

Need help.. urgent