[FieldTrip] add channels on an existing template for EEG layout

[Strinzel at students.uni-marburg.de]

Hello everyone,

I am using FieldTrip to analyse my EEG data recorded with a Brain  
Products system. I recorded EEG data from 32 electrodes (Fp1, Fp2, F7,  
F3, Fz, F4, F8, FT9, Fc5, Fc1, Fc2, Fc6, FT10, T7, C3, Cz, C4, T8,  
TP9, Cp5, Cp1, Cp2, Cp6, TP10, P7, P3, Pz, P4, P8, and Oz, plus 2  
ocular electrodes (O1 and O2), according to the extended 10/20  
international system) with ground located between Fp1 and Fp2 and  
reference electrode located on FCz.
I can't find a layout like discribed above on the fieldtrip webpage  
http://fieldtrip.fcdonders.nl/template/layout but I know that  
fieldtrip also provide the possibility to prepare a layout with the  
ft_prepare_layout  function.

How can I add channels on an already existing template like the  
easycapM23.mat template?
I want to add Oz and the ground, and reference electrode and I want to  
remove the following channels: AFz, PO9, O1, O1, PO10.

Thanks
Anna-Maria