Thanks for the markings thing confirmation, I finally understood what CME Error 10 meant \o/
I can also confirm that it works smoothly with an Samsung Evo 16G, testing and failing with class 10 Kingston and Sandisk in 8gb and 16gb.
For IMEI, AT+EGMR seems to do the trick. Use at own risk, [legal bla bla]... #2c
GSM> AT+EGMR=1,7,490154203237518
AT+EGMR=1,7,490154203237518
OK
GSM> AT+CGSN
AT+CGSN
490154203237518
OK