Hi Anand Nathan,
Indeed RadSiteMapDataSource is designed to instantiate an XmlSiteMapProvider whenever the SiteMapFile property is set. This is so because otherwise the RSMDS control should instantiate a provider it does not know at all and it will not know how to configure it.
If your provider uses the SiteMapFile property of the RSMDS control then your approach of first setting the file and then overriding the XSMP is completely valid.
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