Boot Camp partition disappears upon Tuxera NTFS installation

I would suggest to first install Windows 7 on the new partition as a new installation.

Then, within Windows 7, Restore your computer from a system image backup using Control Panel -> Recovery -> Advanced recovery methods -> Use a system image you created earlier to recover your computer, and then follow the steps.

If worse comes to worst, you can always mount the .vhd in Disk Management to retrieve your data.

EDIT

I have found new info from this article using Acronis True Image Home 2011 (trial version available):
Restoring Windows 7 VHD Backup Files with Acronis True Image Home 2010.

The article says:

Windows 7 has a special System Reserved Partition, which is hidden and contains boot files. This partition can be viewed in Windows Disk Management (Start-Run -> diskmgmnt.msc).

When making an image of your Windows system using the Windows 7 Backup tool, it will create a separate .vhd file for each partition that is in the system, including the System Reserved Partition.

If you choose to restore your system partition from the created Windows 7 Backup .vhd files, you will need to restore the whole disk where this system partition is.

Solution

1. Boot from Acronis Bootable Media and select Acronis True Image Home (Full version)
2. Click Recovery, browse to your Windows 7 Backup .vhd files and select any of the files
3. Once selected, right-click on the .vhd file and select Recover
4. Select Recover whole disks and partitions and click Next
5. Check the partition to recover
   

This approach has failed if you are warned that all data on the destination disk will be erased:

The standard process is to start with a single Mac partition (HFS+ format), then run Boot Camp Assistant. It'll split the drive, and create a FAT32 partition for Windows (which will be converted to NTFS later), and also play some tricks with the disk's partition map to turn it into a hybrid GPT+MBR format (note: this is the reason you should use BCA rather than partitioning it yourself). Then, you boot from the Windows installer disk, have it reformat the FAT partition to NTFS (note: be very careful how you do this, so it doesn't damage the partition map and/or Mac volume -- BCA has instructions, read them) and install Windows. Finally, put in your OS X install disk, and Windows will see it as a driver install disk (incl. a driver to get access to the Mac partition).

Note that Mac OS X can read NTFS, but cannot (by default) write to it; you can change this (see Ryan's answer for instructions), but I've heard of cases where it's corrupted the NTFS volume. Apple leaves this disabled for a reason...