MATLAB: Legend in several columns

legendmulticolumnplot

Hi,
Every time I wanted to split my legend into more than one column I always used the function "columnlegend".
Now i am creating plots with a loop, as below:
legendLables=[];
for iM=1:length(Mvec)
plot(Xvec,F(iM,:), '*-', 'LineWidth',3,'Markersize',3); hold all
legendLables=[legendLables,{['$M=' num2str(Mvec(iM)) '$']}];
end
In this case the function columnlegend does not work, when I use:
columnlegend(6,legendLables,'NorthWest');
or
columnlegend(6,legendLables{:},'NorthWest');
Coudl you please help me?
Thanks in advance!