Should I use a deployment diagram with the OS and AS as execution enviroments and the rest as components (or maybe the portal server should be a device as well)? Any sugestions?
First some definitions:
A deployment diagram is a physical view of some sort of solution.
A component diagram is a logical view of the same solution.
Of course both have something in common (some components will propably also appear as devices and vice versa) but in general it is not a good idea to mix it up because you will usually end up with a confusional view showing at least all and nothing.
The portal server is a component if we talk about the view on it as a piece of software talking with other pieces of software via some sort of interchange protocols (SOAP, HTTP, etc.).
The portal server is a device if we talk about it as a physical thing (mostly a server) with parameters, network connectors, data base connections (physical, not logical), etc.
And now the maybe confusing thing: The portal server can also be a physical sw component, if we talk of it as a deployed piece of software consisting of bits and bytes with parameters (but with no connection to other software pieces because that would be a logical view).
Physically your application/portal server component does not have a connection to eg the operating system (leaving aside the lower physical main board connectors like CPU, PCI bus and DMA

).
Oliver