Hi 8ball,
When Manila ATC tells you to "remain VFR" or "maintain VFR", what he really means is to "stay in VMC". It is just a reminder which he usually issues during times when weather conditions are clearly visual but the visibility from their vantage point is at or below the required minimum (usually due to haze or smog). This is also because they merely 'eyeball' the visibility due to lack of transmissometers at RPLL. Consider yourself lucky to have been cleared to runway 13.
They used to allow 'Special VFR' into 06/24 but this privilege has since been revoked. Don't ask me why.