Image analysis and processing using DWT and SVD

Since i am very new user to matlab, i want to ask about watermarking project related to DWT and SVD. Basically my project is to decompose host image using 2 level dwt and apply svd to HL1 subband and then embed watermark using svd. The objective is to find the optimize scaling factor.

For now, i am able to do until DWT decompostion (2 level). But unfortunately, i have problem on applying svd to HL1 subband. I hope you guys can help me.