Connection of 2different access points

Hi All,
I want to make a Dlink Access point(802.11 G std.,) as a repeater to a Linksys WAP 54 GAccess point.But it is said that we cannot connect two different access points as a repeater or client to the ohter.
MY DOUBT is , as they are of same IEEE std.,(802.11B or G)why they cannot be connected as a repeater or client to the other.
PL help me in this regard.Pl mail me..my mail id is krsvivek@gmail.com

THanks in advance,
Vivekh