Complex search filters

["Chris Brook" <cbrook@v-one.com>]

I have a private schema which has a private structural object (myPerson,
from person, top) which includes an attribute: member (the standard one).
Using ldapsearch, I can retrieve all or any of the myPerson objects
including any or all attributes using a filter: "(member=CN=abcde)", but
"(member=cn=abc*)" returns nothing.  What am I doing wrong?
In addition, how do I retrieve based on a complex filter, e.g. (x=a) or
(y=b).  I tried using the construct in RFC2254 as a template:
"(uid=abc*)(|(cn=xyz*))" but this only retrieves the "uid=abc*" matches and
only gives the base attributes, dn and ufn.
I am using 2.1.21 with a private back-end which works quite happily except
in these conditions.
Any help much appreciated as always.
Chris Brook