Good afternoon Eduardo,
 
You should be able to use the NI-Tuner VIs to lower your desired frequency from 70MHz to 10MHz.  There are a few examples available to give you a good idea of the general NI-Tuner programming flow.  You can find these by going to Start > Programs > National Instruments > NI-TUNER > Examples.
 
You can also have a look at the VIs by going to:
All Functions > Instrument I/O > Instrument Drivers > NI Tuner.  
 
You didn't specify the span required but the NITuner Getting Started.vi should show you how to control both the frequency and span via the niTuner Set Frequency.vi
 
The NI-Tuner Reference Help is a great resource for using your 5600, and is located at Start > Programs > National Instruments > NI-TUNER > Documentation 
 
Please let me know if you have any further questions regarding this issue.
 
Sincerely,
Minh Tran
Applications Engineering
National Instruments