I have also seen this problem many times (2 phones from the same manufacturer as yours). From your question, I understand that you want to force the phone to send an MM periodic location update (which it should be sending anyway).
This is too low level, and there's nowhere you can force this directly in the programming interface. The mobility management procedure is part of the phone stack, and is specified in detail in 3GPP TS 24.008, available from www.3gpp.org. Paragraph 4.2.2 defines when the phone is supposed to send these location updates.
The only other thing would be to try by indirect means to force the phone into a condition where it would send a location update. You might be able to do that by trying to select another network manually. If it's successful, and you then manually re-select your home network, then you would trigger a location update. If it's rejected and falls back to its home network, then I think a location update would be triggered as well. But there would also be small costs to this - battery use while it does a networks scan, and time lost while it scans and does manual network selection. (My personal experience is that the lost calls don't happen often enough to justify this.)