I just re-read your follow-up post and realized I answered the wrong question.
You are correct. The Resource Files only contain the standard profile entries. You have two options. 1) Add your new fields to the standard resource file or 2) create a "portal specific" resource file containing only your added fields.
The main difference is that if you add your new entries to the standard resource file they will be visible to administrators of any portal within your DNN install. If you create a "portal specific" resource file and put your custom entries in there then they will be visible only to the administrator of the specific portal. The way this is done is the language editor first loads the standard resource file. Then it loads any "portal specific" resource file if one exists. The results displayed in the language editor is in effect the "merged" files.
Regardless of which way you choose adding new entries required manually adding them to the file using a text editor. This will require file-level-access to the web server. I prefer option #2 (portal specific respurce files). Read on and I will detail the steps.
"Portal specific" resource files are named the same as the base resource file with "Portal-x" injected into the name (the x is the numeric portalID that the resource file is being used on). Since we are talking about Profile Properties, the standard resource file name is "Profile.ascx.resx". You will find this file in the Admin\Users\App_LocalResources folder under your DNN root.
Let's say that the portal you are creating the custom entries for is portalID 3. The "portal specific" resource file will need to create will be named "Profile.ascx.Portal-3.resx".
First, I make a copy of Profile.ascx.resx and rename it "Profile.ascx.Portal-3.resx".
Next, I open the file using my favorite text editor (PSPad, it's free and available at http://www.pspad.com) and delete all the existing entries. I may leave one or two if I can use them for copy and past to create my new ones. Take special note to leave the existing header intact -- there will be a number of xsd... and resheader... entries at the top. Also, the very last line must be </root>. You will be deleting all the <data> </data> blocks and replacing them with your own.
NOTE: Before deleting the existing entries note the use of them. In many resource files you will see three or four entries for each data element. ElementName.Text, ElementName.Help, ElementName.Error and ElementName.Required. The suffixes used have special uses and the entire entry IS CASE SENSITIVE!
.Text is the value used for the text of the label, .Help is the value used for the help display, .Error is the message displayed is a field fails validation (if you have a validation rule defined) and .Required is the message displayed if a user does not make an entry in a required field.
Also note that in the case of Profile Properties all entries begin with "ProfileProperties_" and are followd by the actual field name of the profile property (i.e. "ProfileProperties_LastName.Text"
With all that said, create your entries in such as below...
<data name="ProfileProperties_MyProfileProperty1.Text">
<value>My Profile Property 1:</value>
</data>
<data name="ProfileProperties_MyProfileProperty1.Help">
<value>Please enter the value for My Profile Property 1</value>
</data>
<data name="ProfileProperties_AnotherProfileProperty.Text">
<value>Another Profile Property:</value>
</data>
<data name="ProfileProperties_AnotherProfileProperty.Help">
<value>Please enter the value for Another Profile Property</value>
</data>
<data name="ProfileProperties_AnotherProfileProperty.Required">
<value>Another Profile Property is a required field</value>
</data>
Sorry for being so long winded! I hope this helps.
Regards,
Chuck R.