InfoPath Dev

I have been searching for quite some time on a way to do the following, so I am hoping someone can shed some light. 

I have a Sharepoint list that has 2 columns, name and URL.   I also have a repeating table with two fields in it.  The first field is a drop down menu with the selections being populating from a Sharepoint list (name column).  The second field is a text field that I want to populate the URL value from the same sharepoint list based on what was selected in the drop down menu.  So what I have done is to setup a rule with a filter to populate the field from the secondary data source when the drop down field is not blank.  This works however the following happens:

 1. If I change the drop down menu selection after I original select it, the rule will not populate a value

2. If I add in another row, the rule will not populate a value into the 2nd field. 

I am assuming that this is because I am using the filter in the rule, so when the form goes to run the rule again after the field is changed or another row is added, that the system is still filtering the seconday data source and can't find any data to populate into the 2nd field. 

Does anyone have any suggestion.  I am fairly new to programming so ideally looking for a non-code or very limited code solution for this. 

 THanks 

Once go through the below link. In this link, they have used the xml as the secondary data source, you can use the sharepoint list as secondary.

http://www.infopathdev.com/blogs/matt/archive/2006/04/18/Automatically-Populate-Fields-from-a-Drop_2D00_Down-Selection.aspx

Thanks for the info.  That works when I initially select a value from the drop down list.  However, after I initially select a name from the drop down list, if I decide to choose something else from that list, then it wont re-look up this information to populate my second field.