<p>For instance, my query is like the following using SQL Server 2005:</p>

<pre><code>SELECT * FROM Table WHERE FREETEXT(SearchField, 'c#') 
</code></pre>

<p>I have a full text index defined to use the column SearchField which returns results when using:</p>

<pre><code>SELECT * FROM Table WHERE SearchField LIKE '%c#%'
</code></pre>

<p>I believe # is a special letter, so how do I allow FREETEXT to work correctly for the query above?</p>

Quoting a much-replicated help page about Indexing Service query language:
To use specially treated characters such as &, |, ^, #, @, $, (, ), in a query, enclose your query in quotation marks (“).
As far as I know, full text search in
```
MSSQL
```
is also done by the Indexing Service, so this might help.