You can use this technote to specify the location:

http://support.veritas.com/docs/319157

Configuring analytics database locations
Details:
Configuring analytics database locations

When you enable a case for analytics, all the items in the case must be fetched from Enterprise Vault into the customer database, and indexed. This requires a large amount of disk space. Discovery Accelerator lets you define locations to host the analytics table file groups and indexes. You can add more locations when you need more disk space.

The Customer page of the Accelerator Manager Web site lists existing analytics database locations, and lets you add more. Next to each location, check marks in the Table File Group and Full Text Indexes columns show whether the location is used for table files, search indexes, or both.

When you plan and configure analytics database locations, consider the following:

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The volume of data. The collection and indexing of analytics data can generate very large databases and index files. As a rough guide, collecting one million items that are all 20 kilobytes in size can produce a database that is 40 gigabytes or more in size. However, this can vary from one environment to another.
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Performance. Host each database location on a physically separate disk. If you have more than one analytics database location, Discovery Accelerator uses them in rotation to spread the data and the disk access requirements.

Each Discovery Accelerator case uses only one location for the search index and one location for the database.

The following examples show two valid configurations for analytics database locations.

To add a database location for analytics

1.

Browse to the Accelerator Manager Web site.
2.

Right-click the appropriate customer, and then click Properties.
3.

Under Database Locations For Analytics, click New Location.
4.

Enter the path to the new database location. Note the following:
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The database locations must reside on the SQL server, and you must use local paths to refer to them. For example, do not use UNC paths to refer to database locations.
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The Accelerator Manager Web site does not verify that the specified locations exist. You must ensure that the paths are valid.
5.

Check Table File Group, Full Text Indexes, or both.
6.

Click OK next to the new location.
7.

Repeat steps 3 through 6 if you want to add more database locations.

That's fine, but the full text search option does not use that path to develop the full text XML files. In fact, it uses the temp folder location of the user account that the SQL server was installed upon.

So by enabling with the options above, the risk of filling up the drive with the full text information still exists. The best practices would need to include a way to relocate the full text search service temp folder. I have found it for SQL 2000 but not 2005 yet.

Sorry, misuderstood your post. 
You could just change the environment varible for that users temp folder to a location other than the c drive.

I have not forgotten about this. I am creating a new drive to store these temp files as they are created since the C drive just doesn't have the room to do this. I should know more by the end of the week.

I marked Wayne's as the solution. Changing those registry keys will indeed relocate the TEMP folder for the Full Text Searching.

Thanks.