what can I do after I check if the SP20 have the cgminer4.7.0 or 4.8.0?
in the pool configuration does the #xnsub parameters goes after or before the stratum+tcp:URL address?
If you have cgminer4.7.0, then first update your miner to the latest firmware. And then you have to use SSH (download putty on windows or use "ssh" command on linux/mac). You can connect as "root" (password "root") user to your miner's IP address and then issue these commands:
cp /etc/bin/cgminer /etc/bin/cgminer.orig
cp /cgminer-extranonce /usr/local/bin/cgminer
cp /cgminer-extranonce /etc/bin/cgminer
Then set your pool connection URL like this:
stratum+tcp://stratum.westhash.com:3334#xnsub
or
stratum+tcp://stratum.nicehash.com:3334#xnsub
And restart miner.
Now you'll notice cgminer4.8.0 version on your miner's home page and extranonce should be enabled.