I had done with the MBD-220HU but then that modem was broken twice and I have renounce.
I remember you had to start without connecting any wires tinyconre network, or connect via "dial-up modem" not working.
At the time I did the tests with a ubuntu live, once I get a certainly configuration working, then I tried to make it work in tinycore.
I also looked for answers in the official forum:
http://www.draisberghof.de/usb_modeswitch/bb/viewtopic.php?p=4406#4406Currently I have only the pen E173, but I could not get it to work, I connect through windows (cross cable).
I took notes, but I can not see if they are correct, I translate them to you quickly:
1)install usb-utils, and enter command "lsusb", annotate the output, insert key and reenter "lsusb", the new entry in second output is your modem (in my case is Bus 001 Device 007: ID 1c9e:f000)
2) install modeswitch and wvdial, I remember that a restart is required.
after restart insert the internetkey, wait a few minutes to do allow modeswitch to do its job (transform the device from mass storage to analog modem) and retype "lsusb", if string of modem is changed modeswith work correctly.
2bis) if the string remain the same you check if a file with the name of your device is in /usr/share/usb_modeswitch/vendor:product, otherwise you have to search in internet. (the command to tell to modeswith to swith a devise usb_modeswitch -c /usr/share/usb_modeswitch/vendor:product, but it should be automatic)
3) Once the modem has been properly recognized and switched (control with lsusb) you mount a modem properly with :"modprobe usbserial vendor=0xvendor product=0xproduct" (take valor from lsusb vendor --> xxxx:xxxx <-- product)
4) If all going well you must see in /dev/ ttyUSB2 ttyUSB3 ttyUSB1 ttyUSB0, for connect i use 2
5) edit /etc/wvdial.conf according to your key (search in internet), You sure you did not put an ethernet cable, I do not remember what was the reason but it gave me problems, otherwise reset. Control /etc/resolv.conf , to be sure you can use 8.8.8.8 and 8.8.4.4 (google dns)
9) start connection with sudo wvdial (and remember store /etc/wvdial.conf and /etc/resolv.conf to your backup file of tinycore)
All operations should be automatic unless wvdial configuration and its launch.