you are absolutely right, I never came to that situation (i generally always compile them altogether in one file)
The compiler will find it if you specify
PHP Code:
A<int>::A()
{


but that's hardly usefull :/
might be an ugly solution but including a macro which with you can declare which instantces you need (and it will expand to specifications with the accurate contents)
but i'd say put them all in the same file.