This might get you started:
This is not a beginners project to install, but it does work as you requested. It'll be easier if you have FMAdvanced.
The template matches the invoice record where you are selecting a company to a company record by the ID number of that company record. That's why you saw a number in the field when you removed the value list format by returning it to edit box format. If you use Manage Value lists to examine the set up for this field's value list, you'll find that it really lists two values: the ID number in column 1 and the name in column 2. Settings in the value list hide the first column, but data from the first column is what is actually entered into the field. This is a good way to go as company names are subject to change and you don't want to break links in your database just because you updated a company name in your database.
It's main limitation is that it doesn't work for long lists of values. But there are other options that will prune that list down to a more manageable size.
If your companies fall into fairly obvious categories, you can use a conditional value list where you select a category in one field and then when you click on the company field, you see a list of only the companies that fall in that company. (And it's fairly easy to set up a table of companies where a company can fall in more than one category.)
You can also use a drop down list of names with the auto-complete feature, but then a script kicks in when you make a selection that looks up the ID number of that company and enters it into the correct field for you. This allows you to use auto-complete while still working with relationships based on ID numbers.
You can also use search portals where the list of records in the portal filters down as you enter more and more text. Clicking a row in the portal then enters the ID number of the clicked portal record.
Some links on conditional value lists:
Forum Tutorial: Custom Value List?
Knowledgebase article: http://help.filemaker.com/app/answers/detail/a_id/5833/kw/conditional%20value%20list
This demo file illustrates the auto-complete value lists and several key by key search portals: http://www.4shared.com/file/plr_jbkk/EnhancedValueSelection.html
Feel free to post follow up quesitons here if those links aren't enough to get your value lists working correctly.
I'm going to attempt re-creating the last demo file you linked there. I dissected it and wrote it all out on foolscap. How would you recommend I begin trying to put this into my project? I don't wanna start and then have to re-start because I got off on the wrong foot haha.
Please and thank-you!
Since I don't have a copy of the productivity kit, I can't really spell out the details.
I can suggest selecting the method (The demo illustrates a number of different approaches) that you like best and carefully isolating which scripts, triggers, relationships are needed for that one specific technique. Then compare what the script does to what you need to happen when you select a company. The scripts in the demo are designed to populate fields in a portal. As such, most create a new record in the portal table--what you need may not require creating a new record and thus the script you'd use would need to be different.
Just wanted to note that I had that same problem in the beginning. Until I found out that you can just make a dropdown.
Even if that is made using an Id field as the first field and for instance the company name as second field.
Even if you only show the second field you can just click the dropdown and start typing.
If you type fast enough you can type multiple letters and the first company with that name is highlighted.
If you type slowly you will always go to the company that has the letter you just typed as first letter.
Try it out.