Spacing several instances of one standard cell using implant spacing rule

Well this is my very first post here so first of all good afternoon!

Here is my problem :

I'm using Encounter to place and route an IP in which i want to space somes instances of the same standard cell by a fixed value.

What i've found in the lefdef reference manual (version 5.8) is to use the SPACING attribute of an IMPLANT layer as explained in pages from 154 to 156.

I've defined a rectangle which is not covering the whole standard cell in the horizontal direction (to avoid the abutment case) in the OBS section by using the implant1 layer i've created in the technology lef. My spacing rule is set but it looks like Encounter is not taking this into account as the cells are still very close one to another.

What i want is to have what is described in the lefdefref manual in Figure 1-75 on page 156.

I've read about the honorImplantSpacing option but this is quite different as it requires to have at least two implant layers.

Thanks a lot if anybody here can help!

Best Regards.