I don't know how to rotate a PF, I don't think it's possible (happy to stand corrected) , but I know how to rotate a perlin 3D noise. Copy and paste the below into TG2, and play with the rotate vector node.
Cheers,
Frank
<terragen_clip>
<constant_scalar
name = "Constant scalar 02"
gui_use_node_pos = "1"
gui_node_pos = "-1160 300 0"
gui_group = ""
enable = "1"
input_node = ""
gui_use_preview_patch_size = "0"
gui_preview_patch_size = "1000 1000"
scalar = "22"
>
</constant_scalar>
<constant_scalar
name = "Constant scalar 01"
gui_use_node_pos = "1"
gui_node_pos = "-1300 260 0"
gui_group = ""
enable = "1"
input_node = ""
gui_use_preview_patch_size = "0"
gui_preview_patch_size = "1000 1000"
scalar = "300"
>
</constant_scalar>
<rotate_y_vector
name = "Rotate y vector 01"
gui_use_node_pos = "1"
gui_node_pos = "-1360 320 0"
gui_group = ""
enable = "1"
input_node = "Get position in texture 01"
gui_use_preview_patch_size = "0"
gui_preview_patch_size = "1000 1000"
angle_about_y = "173.25"
>
</rotate_y_vector>
<perlin_3D_scalar
name = "Perlin 3D scalar 01"
gui_use_node_pos = "1"
gui_node_pos = "-1340 200 0"
gui_group = ""
enable = "1"
input_node = "Rotate y vector 01"
gui_use_preview_patch_size = "0"
gui_preview_patch_size = "1000 1000"
scale = "Constant scalar 01"
seed = "Constant scalar 02"
>
</perlin_3D_scalar>
<get_position_in_texture
name = "Get position in texture 01"
gui_use_node_pos = "1"
gui_node_pos = "-1380 360 0"
gui_group = ""
enable = "1"
input_node = ""
gui_use_preview_patch_size = "0"
gui_preview_patch_size = "1000 1000"
>
</get_position_in_texture>
</terragen_clip>