I ran into the same kind of requirement - here is my code that you can modify to suit for custom fields.

Controller code to search for Solution details based on a CaseId passed in (with test method at the end):

// Controller used by CaseSolutions component to find all related Solutions for a single Case
public class findCaseSolutions {
    // resulting list of Case Solutions
    public List<CaseSolution> solutions {get; set;}
    // Id value of case sent into controller
    public ID CaseId {get; 
        set{
            CaseId = value;
            // if there is a value passed in, query the CaseSolution table for solution details linked to the Case
            if( CaseId != null ) {
                solutions = [select solution.SolutionNumber, solution.SolutionNote, solution.SolutionName from CaseSolution where caseId = :caseId];
            }
            // if there is nothing set in, return an empty list
            else {
                solutions = new List<CaseSolution>();
            }    
        }
    }
    
    // constructor for controller
    public findCaseSolutions() {
    }

    // test method
    static testmethod void testController(){
        // create a Case and 2 Solutions
        Case c = new Case(subject='testing');
        insert c;
        Solution s1 = new Solution(solutionname = 'solution 1', solutionnote = 'solution text');
        insert s1;
        Solution s2 = new Solution(solutionname = 'solution 2', solutionnote = 'solution2 text');
        insert s2;
        // first call controller without linking case and solution
        findCaseSolutions find = new findCaseSolutions();
        find.caseId = c.id;
        system.assertequals(find.solutions.size(), 0);
        
        // now link solutions to case
        CaseSolution cs1 = new CaseSolution(caseId = c.id, solutionid = s1.id);
        insert cs1;
        CaseSolution cs2 = new CaseSolution(caseId = c.id, solutionid = s2.id);
        insert cs2; 
        find = new findCaseSolutions();
        find.caseId = c.id;
        system.assertequals(find.solutions.size(), 2); 
        
        // call it without sending a Case id in
        find = new findCaseSolutions();
        find.caseid = null;
        system.assertequals(find.solutions.size(), 0);     
    }
}

Then I build this component to display the Solution details returned.  My template is in  plain text so I didn't use a dataTable component or anything fancy that doesn't work in plain text.

<apex:component controller="findCaseSolutions" access="global">

    <apex:attribute name="CaseId" description="Case Id for which we are finding Case Solution records" type="String" required="required" assignTo="{!CaseId}"/>
    <!-- using a simple repeat component so this can be inserted into a plain text email template -->       
    <apex:repeat value="{!solutions}" var="s">
        {!s.solution.SolutionNote}
    </apex:repeat>

</apex:component>

 And finally I included this component into my visualforce Email Template:

<messaging:plainTextEmailBody >
Dear {!recipient.Name},

Here is your solution detail: <c:CaseSolutions CaseId="{!relatedTo.Id}"/>
</messaging:plainTextEmailBody>

The only downside of this is you can't include the Solution attachments.  We can query for them in the controller but I don't see a way to attach them into the email template.  I added an Idea for that - vote if you think it would be useful.

You can add any custom fields you need into the controller query.

Hope that helps.

Niki

www.vankerksolutions.com