typing with XML Schema

[Ho-Kuo Chan <hchan@wavesat.com>]

Hi,
I'm not sure if this is the correct forum for my question, forgive me if 
it is not and feel free to point me in the correct direction for it. 
What I would like to do is create a new simpleType that is identical to 
a built-in type, without any restrictions. Consider an example from C 
language:

typedef uint16_t my_element_type;

What's the point? Well doing this allows me to use the "my_element_type" 
everywhere and if it's size ever changes from say the 16 bits defined to 
say 32 bits, I can just replace the line above with:

typedef uint32_t my_element_type

and the update becomes automatic throughout.

I thought something like this would have been perfect but is iilegal:

<xsd:simpleType name="my_element_type" base="xsd:unsignedShort"/>

then I tried this:

<xsd:simpleType name="my_element_type">
    <xsd:restriction base="xsd:unsignedShort"/>
</xsd:simpleType>

but it too is illegal.

Is there an elegant way to do this? Thanks in advance!
-- 
HK Chan