Apparently you ignored repeated warnings that the disk was being converted to Dynamic - meant only for partitions spanned across multiple HD's - when you created H in Disk Management.
The only way to do this non-destructively is to move the data off of H and delete it in Disk Mgmt or using PW CD. It will now convert.
To convert it use PW bootable CD v. 4.2 which is the last version which this feature was offered for free. Download and burn ISO to CD from this link: pw422.zip ISO - Windows Live
Boot the CD, delete H if you have moved the data off and not yet deleted it, click OK. Then click on the Disk # to highlight the HD, from Disk tab select Convert to Basic, OK, Apply both steps.
Once conversion is complete, rightclick on the space where H was and Create New Logical partition. Any addiitonal partiitions can be added adjacent to the Logical using PW CD to Resize left or right, then Create New Logical.