after tests i've been doing in the past few days i found that QT mobile hotspot does work well, but only if i manually disconnect the Wifi connection before starting it.

so i execute this before start and it works great:

dbus-send --print-reply --system --dest=com.nokia.icd2 /com/nokia/icd2 com.nokia.icd2.disconnect_req uint32:0x8000

Thanks.