finally got it to work with a another hack inside that hack.

src/Actor.cpp

@@ -311,6 +311,11 @@ void Actor::BeginDraw()		// set the world matrix and calculate actor properties
 		m_pTempState = &tempState;
 		tempState = m_current;
 
+		// XXX HACK! We can't really determine the active player outside Draw() so
+		// figure it out just for this clock type here.
+		if( m_EffectClock == CLOCK_BGM_BEAT_PLAYER_ACTIVE )
+			m_fSecsIntoEffect = g_vfCurrentBGMBeatPlayerNoOffset[m_ActivePlayerNumber];
+
 		const float fTotalPeriod = GetEffectPeriod();
 		ASSERT( fTotalPeriod > 0 );
 		const float fTimeIntoEffect = fmodfp( m_fSecsIntoEffect+m_fEffectOffset, fTotalPeriod );
@@ -680,16 +685,12 @@ void Actor::UpdateInternal( float fDeltaTime )
 		break;
 	}
 
+	case CLOCK_BGM_BEAT_PLAYER_ACTIVE:
 	case CLOCK_BGM_BEAT:
 		m_fEffectDelta = g_fCurrentBGMBeat - m_fSecsIntoEffect;
 		m_fSecsIntoEffect = g_fCurrentBGMBeat;
 		break;
 
-	case CLOCK_BGM_BEAT_PLAYER_ACTIVE:
-		m_fEffectDelta = g_vfCurrentBGMBeatPlayer[m_ActivePlayerNumber] - m_fSecsIntoEffect;
-		m_fSecsIntoEffect = g_vfCurrentBGMBeatPlayerNoOffset[m_ActivePlayerNumber];
-		break;
-
 	case CLOCK_BGM_BEAT_PLAYER1:
 		m_fEffectDelta = g_vfCurrentBGMBeatPlayer[PLAYER_1] - m_fSecsIntoEffect;
 		m_fSecsIntoEffect = g_vfCurrentBGMBeatPlayerNoOffset[PLAYER_1];

src/NoteField.cpp

@@ -768,6 +768,8 @@ void NoteField::DrawPrimitives()
 {
 
 	// XXX Hack: Set Actor's active player number so the notes get the flashing that matches the steps.
+	// save the active player number (so they can nest)
+	PlayerNumber pnLastActivePlayerNumber = m_pPlayerState->m_PlayerNumber;
 	Actor::m_ActivePlayerNumber = m_pPlayerState->m_PlayerNumber;
 
 	//LOG->Trace( "NoteField::DrawPrimitives()" );
@@ -1252,6 +1254,9 @@ void NoteField::DrawPrimitives()
 	}
 
 	cur->m_GhostArrowRow.Draw();
+	
+	// restore the active player number
+	Actor::m_ActivePlayerNumber = pnLastActivePlayerNumber;
 }
 
 void NoteField::FadeToFail()