Dynamically Passing Parameters From ASPX Host

I am looking for someone to provide guidance as to whether the following solution is the prescribed way of going about this. Yesterday I started working on a problem that, at first blush, seemed pretty simple and straightforward. I need to pass a few parameters from an ASPX code-behind, which hosts a Silverlight object tag, to the code-behind of one, or more, of the Silverlight user controls within the hosted Silverlight application. So, after doing some research, this is the basic solution I developed.

I found out that an attribute can be added to the object tag called initParams, a comma delimited list of parameter names and values can be added to this attribute. Like so.

<object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%">
<param name="source" value="ClientBin/SampleApplication.xap"/>
<param name="onError" value="onSilverlightError" />
<param name="background" value="white" />
<param name="minRuntimeVersion" value="3.0.40624.0" />
<param name="autoUpgrade" value="true" />
<param name="initParams" value='DealerId=17' />
</object>

This is fine, except that the DealerId parameter is basically hard-coded in the object tag, not real useful. The next thing that I did was replace this object tag with a literal control, and set the text of the literal control within the page's code-behind to the value of a StringBuilder (where I built up the full object tag along with dynamically adding the correct DealerId value). In the following example, the DealerId is hard-coded, but you get the idea.

var sb = new StringBuilder();
sb.Append(@"<object data=""data:application/x-silverlight-2,"" type=""application/x-silverlight-2"" width=""90%"" height=""80%"">");
sb.Append(@"<param name=""source"" value=""ClientBin/Ascend.SilverlightViewer.xap""/>");
sb.Append(@"<param name=""onError"" value=""onSilverlightError"" />");
sb.Append(@"<param name=""background"" value=""white"" />");
sb.Append(@"<param name=""minRuntimeVersion"" value=""3.0.40624.0"" />");
sb.Append(@"<param name=""autoUpgrade"" value=""true"" />");
sb.Append(@"<param name=""initParams"" value='");
sb.Append(@"ServiceUrl=");
sb.AppendFormat("http://{0}{1}", Request.Url.Authority, ResolveUrl("~/ReportService.svc"));
sb.Append(@",DebugMode=Full");
sb.AppendFormat(@",DealerId={0}' />", 40);
sb.Append(@"</object>");
litObjectTag.Text = sb.ToString();

My goal, if this initial design is sane, is to then pull this object tag creation into a server control, which will have a DealerId property, which in turn will be set within the hosts code-behind. At this point, I have the host dynamically adding parameter values to the object tag's initParams attribute, the next step is to get these values and leverage them within the hosted Silverlight application. I found a few articles to help out with this; I'm creating a public dictionary within the App.xaml.cs, and setting it within the Application_Startup event.

public IDictionary<string, string> InitConfigDictionary;
private void Application_Startup(object sender, StartupEventArgs e)
{
InitConfigDictionary = e.InitParams;
this.RootVisual = new MainPage();
}

Now, I can access this public dictionary from the code-behind of any .xaml user control, like this.

App app = (App)Application.Current;
var dealerId = app.InitConfigDictionary["DealerId"];

This design works just fine, I'm just looking for some guidance, since I'm new to Silverlight. Once again, the implementation works, but it seems like a whole lot of work to go through just to pass a dynamic value from the host to the .xaml files. Because I'm new to Silverlight, I'm hoping that someone with more experience can say that either:

a) Patrick, you're insane, why are you going through all this work when clearly in Silverlight you would accomplish this through the use of "xxxxxx".
b) Yeah, Patrick, it's a drag, but this design is basically what you have to do in Silverlight.