Earlier, I wrote about how to use UMTS with the Archos 3G USB UMTS stick in Plasma Active on Archos G9 . There I introduced a number of custom stuff like changed kernel config, additional tools (usb-modeswitch), or additional configuration (like udev rules). This required quite some manual work in order to get everything in place.
Fortunately, in the meantime, this had been integrated into the testing images of Plasma Active. So you get very much of the requirements out of the box when you install a fresh Plasma Active testing image. Great thanks to mdfe for merging this into the official testing repository.
You still need to set up a network manager configuration for the WWAN connection. Additionally, you might need to disable the PIN of the SIM card; I had some issues that I could solve (or at least circumvent) by disabling the PIN. For information on how this can be done please see my other, older posts about this. There you also find some information on how to debug the WWAN connection.
Note that I sometimes need to connect twice in order to get the connection working (i.e., the first attempt fails and the second succeeds). For now, I don’t know if this is due to bad reception or some configuration issue. But this is nothing I consider a major issue right now.