Haider,
Since AI Read.vi is only capable of reading complete scans (one sample from each channel included in the task), it is not possible to read a different number of samples from each channel. Furthermore, it will not be possible to create seperate tasks for the SCXI-1121's channels because they use the same resources. Thus, you will need to read the greater number of samples (10) from both channels and discard the data you do not need.
Good luck with your application.
Spencer S.