XML dateTime Patterns...

Hi,
 
Is it possible to change the format of a dateTime attribute using
patterns? If yes, can I have some examples...
 
For instance, is it possible to restict the dateTime
(CCYY-MM-DDThh:mm:ss) to just the 'Date' (DD) or "Hours and Minutes"
(hhmm).
 
for example....something like....
 
----------------------------------------------------
 
<xsd:simpleType name="utcDate">

    <xsd:restriction base="xsd:dateTime">

        <xsd:pattern value="DD"/>

    </xsd:restriction>

</xsd:simpleType>

-------------------------------------------------------------------

<xsd:simpleType name="utcTime">

     <xsd:restriction base="xsd:dateTime">

        <xsd:pattern value="hhmm"/>

    </xsd:restriction>

</xsd:simpleType>

----------------------------------------------------
 
Thanks,
Saurabh