제가 실수했군요...
Attachmode 가 naInsert 는 dest node 바로 앞으로 옮기는 것이군요..
나름대로 완벽한(-.-;;) 소스입니다..

void __fastcall TForm1::btn_UpClick(TObject *Sender)
{
        if(!tr_ScanSide->Selected)
                return;

        TNodeAttachMode AttachMode;
        TTreeNode *destNode, *selNode;
        if(tr_ScanSide->Selected->Index == 0)
                return;

        destNode = tr_ScanSide->Selected->GetPrev();
        selNode = tr_ScanSide->Selected;
        AttachMode = naInsert;
        selNode->MoveTo(destNode, AttachMode);


}
//---------------------------------------------------------------------------


void __fastcall TForm1::btn_DownClick(TObject *Sender)
{
        if(!tr_ScanSide->Selected)
                return;

        TNodeAttachMode AttachMode;
        TTreeNode *destNode, *selNode;
        if(tr_ScanSide->Selected->GetNext() == NULL)
                return;

        selNode = tr_ScanSide->Selected;
        if(! tr_ScanSide->Selected->GetNext()->GetNext() == NULL) {
                destNode = tr_ScanSide->Selected->GetNext()->GetNext();
                AttachMode = naInsert;
        }
        else {
                destNode = NULL;
                AttachMode = naAdd;
        }

        selNode->MoveTo(destNode, AttachMode);
}




현정환 님이 쓰신 글 :
: 검색해 보니 나오더군요 ^^;;;;;
:
: 그래서 대충 한칸 올리는건 했는데
:
: 똑같이 했는데 왜 한칸 내리는 건 안되는지 모르겠네요..
:
: tr_ScanSide 가 TTreeView 콤포넌트의 이름입니다..
:
: //================================================
: void __fastcall TForm1::btn_UpClick(TObject *Sender)
: {
:         if(!tr_ScanSide->Selected)
:                 return;
:
:         TNodeAttachMode AttachMode;
:         TTreeNode *destNode, *selNode;
:         if(tr_ScanSide->Selected->Index == 0)
:                 return;
:
:         destNode = tr_ScanSide->Selected->GetPrev();
:         selNode = tr_ScanSide->Selected;
:         AttachMode = naInsert;
:         selNode->MoveTo(destNode, AttachMode);
:
:
: }
: //---------------------------------------------------------------------------
:
:
: void __fastcall TForm1::btn_DownClick(TObject *Sender)
: {
:         if(!tr_ScanSide->Selected)
:                 return;
:
:         TNodeAttachMode AttachMode;
:         TTreeNode *destNode, *selNode;
:         if(tr_ScanSide->Selected->Index == tr_ScanSide->Items->Count)
:                 return;
:
:         destNode = tr_ScanSide->Selected->GetNext();
:         selNode = tr_ScanSide->Selected;
:         AttachMode = naInsert;
:         selNode->MoveTo(destNode, AttachMode);
: }
:
: //==============================================================================