Problem with Huawei Me909s-120 4G modem

Hello,

Recently i bought a routerBoard 912UAG, and 4G card modem Huawei Me909s-120. After the instalation de modem is recognized by the RB.
In the system resouce usb:

DEVICE VENDOR NAME SPEED

0 1:1 Linux 3.3.5 ehci_hcd RB400 EHCI 480 Mbps
1 1:2 Huawei Technologies C... HUAWEI Mobile V7R11 480 Mbps

I configure the ip dhcp-client, and then in LTE interface settings i cant get Info because .. "Couldn't start - Modem does not have serial interface! (6)".
I never get IP Address, but

if a put ignore direct ip modem (the port usb1 is created PPP), i create a ppp-out interface and then i have ip address and internet, but in LTE interface not.
I have installed the routerOS 6.35.4.

How can i solve this issue? To work with LTE interface, not with ppp?

Thanks for the help
Regards