A question about XML Tags

[Jony Joe]

Dear All;
I am a biginner in XML. Currently I am developing a service for CISCO IP
Phone using ASP.Net. The CISCO IP Phone service has to be developed using
XML Tags. For examlpe the CISCO IP Phone Input takes the following form

<CiscoIPPhoneInput>
<Title>Directory title goes here</Title>
<Prompt>Prompt text goes here</Prompt>
<URL>The target URL for the completed input goes here</URL>
<InputItem>
<DisplayName>Name of the input field to display </DisplayName>
<QueryStringParam>TheURLqueryparameter</QueryStringParam>
<InputFlags> </InputFlags>
<DefaultValue>Value</DefaultValue>
</InputItem>
</CiscoIPPhoneInput>

The problem is that the tag QueryStringParam , (which takes the input from
the user and stores it in the "TheURLqueryparameter" which is a parameter
that is appended to the URL in the URL tag), If contained space, the
application doesn't respond. So I don't know if proper standard XML tag
which permits a space is available to habdle this case or not. If I used any
other characters except the sapce, it will work well without any error .

So my concern is this problem releates to XML or not?
I hope that any can help me
Best Regards;
Jony