Query With Multiple Outer Joins Gives Wrong Result

Hello,

My query references 2 related tables: one for persons (PERS) and one for telephone/fax numbers and email addresses (CONT, for Contacts).
The relevant fields are:

PERS
pers_id (long) ---> primary key
pers_forename (text)
pers_surname (text)

CONT
cont_id (long) ---> primary key
pers_id (long) ---> foreign key
come_id (long) ---> foreign key
cont_number (text)

The foreign key come_id refers to a table for contact methods (COME), either "Phone (Home)", "Phone (Work)", "Mobile", "Fax" or "Email".

Now i want to list all persons with their home phone number and email address, also if they don't have one. It seems to be impossible to get it ...
I will explain what happens. Lets start simple: first list all persons with their home phone number (come_id = 1):
SELECT PERS.pers_forename, PERS.pers_surname, CONT.cont_number AS Phone
FROM PERS LEFT JOIN CONT ON PERS.pers_id = CONT.pers_id
WHERE (((IIf(IsNull([come_id]),1,[come_id]))=1));
This works fine. The IIf expression is necessary since we are dealing with an outer join: not all persons have a home phone number. If we would simply put "WHERE come_id = 1" then the query produces only the persons that have a home phone number.

But now i also want to see the email address (come_id = 5):
SELECT PERS.pers_forename, PERS.pers_surname,
CONT.cont_number AS Phone, CONT_1.cont_number AS Email
FROM CONT AS CONT_1 RIGHT JOIN
(PERS LEFT JOIN CONT ON PERS.pers_id = CONT.pers_id)
ON CONT_1.pers_id = PERS.pers_id
WHERE (((IIf(IsNull([cont].[come_id]),1,[cont].[come_id]))=1)
AND ((IIf(IsNull([cont_1].[come_id]),5,[cont_1].[come_id]))=5));
It seems perfectly logical: i added a second alias CONT_1 for the email address. Since this is also optional we have a second outer join, and the WHERE condition should also use an IIf expression.
The result is not correct though: the resulting recordset shows only the persons that have both a home phone number and an email addres or neither!
I have a lot of experience with SQL and queries, but i know i am not infallible. Nevertheless i am quite convinced that i should get all the persons: those that have a home phone number or an email address, or both or neither ...
I hope that someone of you can explain this.