BBOS 10.2.1 Manual mobile network roaming issues

Hey,
I'm a swede that recently started working in Denmark. This means I commute daily and a couple of days ago I signed up with a provider that gives me same-rate in Denmark, but only if I roam on their danish net.

So here's what the issue is, once I cross into Denmark I manually scan and select the correct net.
Normally you'd assume that this means it stays with that net and does not connect to any other unless it's manually chosen right?

Wrong - BBOS 10, for some reason, gladly connects to another net without notification and without prompting to confirm data-services while roaming (set to prompt in settings). It will then stay on that net until connection lost and then jump onto whatever comes next.

This is such a headache and extremely costly. I have tried searching for anyone else experiencing the same issue but my scenario is somewhat uncommon I suppose.

Does anyone have any ideas whatsoever why this happens or atleast how I can work around it?

There seems to no such thing as Preferred Network (RIM; consider this a feature request).
I'm fine with selecting the net manually but it's of little use if manual selection is treated as automatic when roaming.

My setup:
Q5 - Official 10.2.1.2102
Only native apps installed - five in total.

A bit of an update;
I've continued testing/trying to replicate and have actually found the cause of the automatic provider switch when on manual.

To replicate this you need a network provider that only have 3G service:
Mobile network settings:
Network Mode: 3G+2G
Network selection mode: Manual

When connected to the 3G only network; change network mode to 2G only.
What happens then is that the manual selection is actually "ignored".
If this happens due to the lack of 2G service for the operator or lack of check for network selection mode only RIM knows.

The phone switches over to another provider (this is only possible while roaming since your own country's providers probably wont allow "roaming" as such) and will stay there even if Network mode is switched to anything else.

My solution is to use 3G only (no loss really since thats all my provider has anyway).
With this setting the network connection is kindof jumpy though - Many times it wont reconnect to my own provider in my country after a signal loss.

I hope this helps anyone else experiencing strange mobile network behaviour.

I see this issue too. And I can't find a workaround. I'm on the UK network, 3, and I travel to gibraltar, which has an airtime sharing agreement with the spanish networks, so allows calls and data to come out of the standard monthly tariff when you travel to spain. Gibraltar is small, and you can often use the spanish networks if you are close to the border. With my old iPhone (a dirty word here, I know, but bear with me), I can select a spanish network with the manual network setting, and it will stay with that network regardless of signal strength and will merely report no service if out of range. With my BB Passport, the phone I'd much prefer to use, I select manual, and it will, upon losing signal, override my manual settings and default back to automatic, switch to the strongest network, GIBTEL, one I don't have a sharing agreement with, and start charging me high roaming roaming data fees. It's my perspective that this renders the manual selection of a network completely pointless if it switches back to automatic. It's a pretty big oversight on my beloved blackberry and one I can't believe no-one else has fallen foul of. I'm intrigued by your 2G only setting, because my passport doesn't give me that option, just 3G only or 3G+2G. I'm wondering if anyone else out there has this issue. I'm sure we can't be the only two.....