how to customize dvbs2ldpc in matlab

I want to use dvbs2ldpc but length of http://www.mathworks.com/help/comm/ref/comm.ldpcencoder-class.html#bsyh0xo-4 but it has a problem about length of data

how should i customize length of this program regarding my own code and adopt it with my program ?

i found another sample here also http://www.mathworks.com/help/comm/examples/dvb-s-2-link-including-ldpc-coding.html

[Yang Luo]

Hey, mate! Have you solve this problem? I have same question as yours, all the reference I can find says the data length should be k, and k is 32400 which default in matlab.

I can't change my code to match with 32400, how did you solve that? Many thanks!