There are a variety of ways to import files to Content Manager.  If you want granular control you may choose to write some code.  This Powershell script uses a CheckinStyle to import all EML files from a folder.

Add-Type -Path "c:\[CM Binary Path]\HP.HPTRIM.SDK.dll"
$database = New-Object HP.HPTRIM.SDK.Database
$database.Id = "L1"
$database.WorkgroupServerName = "local"
$database.Connect()

$checkinStyle = New-Object HP.HPTRIM.SDK.CheckinStyle($database, "test sec");

$files = [System.IO.Directory]::GetFiles("c:\\junk\\testimport", "*.eml", [System.IO.SearchOption]::TopDirectoryOnly);

foreach ($file in $files)
{
Try
{
    $inputDoc = New-Object HP.HPTRIM.SDK.InputDocument($file);
    $rec = $checkinStyle.SetupNewRecord($inputDoc)
    $rec.Save()

    [System.IO.File]::Move($file, [System.IO.Path]::Combine("c:\\junk\\imported\\", [System.IO.Path]::GetFileName($file)))

    Write-Host "Imported: " $rec.Title + " / " + $rec.Uri
    }
    Catch 
    {
        $ErrorMessage = $_.Exception.Message
        Write-Host "Error: " $ErrorMessage + " / " + $file

    }
}

$database.Dispose()

To use this script:

• set the location of your Content Manager binaries in the first line,
• use your database Id in the $database,
• if your work-group server is not on the local machine set the WorkGroupServerName,
• replace the name in the Checkin Style  Style constructor,
• if you want to import files other than EML change the '*.eml' to something else,
• set the source folder name, also the destination folder in the Move method (ensure this destination folder exists), then
• run the script from Powershell.