How do I copy CustomFields from one company to another?

Hello everyone. 

I want to copy all custom fields from one company to another, but I'm having a hard time understanding how the behind the scenes-logic work.

I'm looking for someone who can help me understand it :)

The following code doesn't copy anything. Why?

#setLanguageLevel 4;

NSContactAgent ca;
Integer origId = 8590;
Integer newId = 8603;

NSContactEntity origComp = ca.GetContactEntity(origId);
NSContactEntity newComp = ca.GetContactEntity(newId);

Map origUdef = origComp.GetCustomFields();

newComp.SetCustomFields(origUdef);
ca.SaveContactEntity(newComp);

Adding the following line updates 'SuperOffice:18', but only 'SuperOffice:18'

Map origUdef = origComp.GetCustomFields();
origUdef.insert("SuperOffice:18", "261"); //THIS LINE

newComp.SetCustomFields(origUdef);
ca.SaveContactEntity(newComp);

..but not if I write it like this:

Map origUdef = origComp.GetCustomFields();
origUdef.insert("SuperOffice:18", "[I:261]");

And here comes the kicker. If I alter the previous code-snippet to the following, suddently '[I:261]' works again.

Map origUdef; 
origUdef.insert("SuperOffice:18", "[I:261]");

I tried something like this, but this doesn't work either:

Map origUdef = origComp.GetCustomFields();
Map newUdef;
for(origUdef.first(); !origUdef.eof(); origUdef.next()) {
    newUdef.insert(origUdef.getKey(), decodeDBValue(origUdef.getVal()));
}

newComp.SetCustomFields(origUdef);
ca.SaveContactEntity(newComp);