first you need the missed call screen plug in.
here is a copy of my .xml for my missed calls plug in, if you just copy and paste the missed calls plug in, into your homescreens xml and then you need to create a picture for the missed calls and name is like filenamemc.jpg and then put that file into the application data/home area and then it will notice the file, like for instance my missed call jpg is melissamc.jpg you would just make the picture you want to be displayed and then save it and put it into the application data/home area of the phone. and then boom it works

you may need to change ur home screen first, and then go back into the one u want and then u will be able to see it.
<!--standard missed calls plugin-->
<plugin clsid="{0BA8ABB8-1F1D-417f-88C6-DA8530E2E7A6}" name="missedcalls" height="220">
<background b-border-width="0" bgimage="\Application Data\Home\
melissamc.jpg" valign="top">
<format state="selected" fgcolor="#000000"/>
</background>
<label halign="left" bgcolor="#000000" fgcolor="#000000" font-weight="bold" x="202" y="155" w="320" h="220" font-size="32">
<format state="nocall" visible="false"/>
<text lang="0x0409">
<calls/>
</text>
</label>
</plugin>
<plugin clsid="{837FC251-FE69-43ad-84E0-EBCEDEBA0884}" name="Iconbar" height="0">
<background b-border-width="0">
</background>
<iconbar bgcolor="transparent" fgcolor="#FFFFFF" y="0" x="0"/>
</plugin>