Let me put my question in simple way with spet by step-
A Team member of mine will create some sections in Test Template and after clicking on that section at the time of creating test Plan instead of default window , i want to have  one search option for lets say 'Product Id' and all these value will come from an Excel file[column] on my machine.

here is the spep by step details what i need to make changes  as per our requirement-
1. First he has created a Test Template(T1) [Manage Text Template-->Create Test Plan Template-->NAME(T1),Description]
2. he has to select 'Available Section', Some of of the options are already there but in our case he has created new Option lets say "Product Id"  and adided to Template T1, then OK.[Add New custom section-->section Name(product Id)--> Description-->Selection Type(Grid)]---> OK.

3. Now, in order to created a test Plan i have used this Template 'T1'  so this 'Product Id' is visible in "sections" of the Test Plan. When i click on this link[Product Id]  a defult window comes up,    my task is to custimize this window and provide one search section to select the "Product Id value" and all these 'product Ids' will come from an Excel file on my Machine.

===> My question is, how can i change this default window and make a search option[one lebel, so when he enters first fews latter all the similar  product id visible and he can select easily], is there any API, any programming language[Java, JavaScript or any other language] i need to use and how or any predefind way already given in RQM?
===> After complating this UI part, how can i read a perticular filed [column] from an Excel file on my machine and set in into that created section('Product Id'). your help would  greatly appreciated.